That's all very relatable. Task-starting and context switching are the bane of my existance.I've had ADHD since I was a teenager, and needed medication to get through college. I ended up quitting due to side effects, I started medication again recently but quit again due to side effects.
One way that I cope is by doing something tangential to a big task or not really effortful. Like if I need to do something in the workshop, I'll wander down there without necessarily intending to start the project, or maybe I'll just clean up or sweep for a minute. By the time I've done that, it's less friction to do the thing.
Or I'll figure out the smallest unit of effort to start a big task. At my job this is easy because there's usually a docker compose, so I'll spin up the stack and setup tmux, and by then I'm already 'working' on the problem (and reminded of what I'm trying to solve) so I might as well try the first solution that comes to mind. Then I'll follow from that to the next thing that occurs to me.
I think I got this technique from Terry Crews, who said he got over his mental block for working out by changing his goal from "I will work out at the gym every day" to "I will physically be at the gym at this time every day." Which means if he was truly not up for working out, he could read a book or something, separating the hard part of the task from the logistical part of the task.