I'm not sure if I have ADHD but your experience sounds so similar to mine. I should maybe get that checked out.
I've recognized in these past couple of years that my focus is garbage and I've been doing some of the things you mention here. I've found that journaling and time blocking have changed everything for me. I work these 20min blocks with short breaks in-between and my focus on tasks has never been better. The journaling too helps me slow down and focus, which is a big plus. It's so easy to rush away, skipping on one random thought to the next without even trying. There are so many times I'll be in conversation and I'll just check out. I don't mean to but it happens and it's embarrassing because I have to ask them to repeat what they just said, and it's not like I was trying to ignore them. Anyway, journaling/time blocking has even helped me with that and it's easier to stay focused while others speak to me. I have a long way to go overall, but it's progress when it comes to learning how to focus.
Anyway, thank you for this post! I really appreciate it.