Previous layouts used
I grew up using the Swedish ISO keyboard, doing some self-taught hunt and peck until my late teens (now 38) when I decided to learn touch typing. A few years later I tried Dvorak briefly but it was very inconvenient as, at the time, I had to use multiple computers that were not mine.

7 years back I moved to ANSI-land and I changed my layout to a US-Intl where I modified the dead keys to be on alt-gr using MSKLC for Windows. The Swedish characters ÅÄÖ were on alt-gr WQP and otherwise I used it as a standard US keyboard. This worked fine, I type maybe 5 % Swedish and the rest a mix of English and programming. Compared to the Swedish ISO qwerty layout I loved having symbols handy on my right pinky and easier access to return.

I haven't spent any effort over the years to try to get fast but I get (got?) around 70 wpm on mixed English text with punctuation from using it for the past 20 years. I had some non-standard habits like taking Q with the ring finger and alt-typing certain combinations but mostly standard. I never touch typed the numbers or symbols other than the most common ones though and I exclusively used the left shift. Overall, I considered my qwerty skills better than average and not in any way an issue for getting work done.

The rabbit hole
Moving forward to this year I discovered the mechanical keyboard community on reddit and thought to myself - wow, that is some serious dedication to lube keyboard switch stems for hours. :) I bought a non-programmable mech keyboard with some brown soldered switches when I moved to ANSI-land and hated it but thought I'd give it another shot to see what the fuss is all about, although with no intention to start lubing switches. Got myself a Keychron V1 and after finding some silent switches I use it as my daily driver at work,

Getting the V1 also meant thinking a bit more on using the keyboard properly so for a month or so I practiced the num/symbols, using the right shift for letters on the left hand and removing any other weird habits I had picked up over the years. This was on TypingClub.com. That site had a lot of exercises (including colemak) but the interface is very bloaty, to the point where it's interfering with the typing speed. Not recommended.

Colemak
Going further down the rabbit hole I also thought I should look into more optimized layouts than qwerty. As I've fortunately never felt any pain or speed issues with qwerty, my goal is strictly to have a more comfortable typing experience. This brought me to Colemak and specifically Colemak-DH (CA).

I decided to install EPKL on Thursday a week ago and immediately start using Colemak DH exclusively. That was... slow and very very frustrating. I had the EPKL small image of the layout visible and typed a character at a time. In the evening I made a layout in VIA for my keyboard so that I could use colemak without having to install epkl or modify OS settings. I also spent all evening practicing on colemak club (recommended!), switching back and forth between levels for variety. Friday was slow and frustrating but I had the layout memorized and didn't have to spend 10 seconds on every key anymore. On the weekend I practiced on Monkeytype (recommended!), initially with default settings and later turning on punctuation and increasing word count. I was at about 25 wpm on the easy settings with too many mistakes (90-95 % accuracy), on rare occasion increasing to 30-35 wpm.

Focusing on accuracy
Realizing that I needed to increase the accuracy to get the correct finger memory I decided to slow down and set a target for myself to get at least 98 %. This I felt was highly useful as the slower speed also made me think more about different bigrams. LD for example was one I struggled with but improved quickly with slower practice. I also appreciated Monkeytype's functionality to repeat missed words. In addition to probably being more effective, not making as many mistakes also made it easier to enjoy practicing. Just over a week after trying the layout for the first time I'm now at 35 wpm for English 10k with punctuation and 98 % accuracy, which I'm very happy about. For me personally I feel like forcing myself to use colemak exclusively has been smoother than I expected and with the first extremely frustrating days in my rear mirror I'm happy I choose this route instead of for example tarmak or a mix of qwerty/colemak. I should have switched on the beginning of a weekend though.

Local characters
Where I would like some advise is the area of local characters. My experience with shifting from ISO Swedish to US Intl ANSI, and the low percentage of writing Swedish I do, has led me to believe I prefer keeping the '"[]{} symbols where they are instead of having åäö as dedicated keys.

Attempt #1: I initially let them be at the same letters as I had before (alt-gr WQP), which resulted in å and ä being in the same physical location and ö moving to the left index. Wow, this was bad. Now that I had experienced typing English with Colemak, having those Swedish characters on bad locations was awful in comparison.

Attempt #2: I quickly put them on alt-gr EIO instead, which was better. I however also realized that my alt-gr key is hard to reach, and switching the alt keys didn't make it better.

Attempt #3: Next I thought about the ; key. I don't program in any language that makes heavy use of it so I had an idea of making it a dead key. Trying out a couple of positions I thought ;l for å, ;n for ä and ;y for ö were the easiest to type. Pressing ; twice to get ; felt acceptable. It works okay I guess, but having vowels on the right index feels very far from ideal given the metric tons of SFB's it causes. Ideas are welcome. I feel like some easily accessible thumb keys would make this a lot easier but I haven't explored that rabbit hole (yet?). While I was modifying the ; thing I also added _[{(< to the home row on my left hand, with ]})> below. The jury is still out on whether I'll use that long term or not.

Practice vs reality
Similar to the experience of others here I find myself struggling more with normal day to day typing than when doing typing tests. I don't know, maybe when I'm busy thinking about what to type I forget to think about how to type it. Overall, while the struggle is real, I keep improving and I believe in a few months I should be able to type freely again and hopefully also with the goal of improved typing comfort accomplished.

Thanks
I appreciate all the work you've all done on creating and improving the layout and making it accessible with things like EPKL and tutorials. I also tried an extend layer and while I ended up moving the the keys around more like miryoku with cut/copy/paste on the top right I definitely see the appeal for the combination of modifiers on the left home row and arrows etc on the other. Very nice!