I know 'me too' comments are not welcome here, so my justification for this reply is that it highlights an apparent minority of folks here who really struggle with all the standard tools for so-called procrastination and so-called productivity.

I agree about the lizard brain motivation. It seems that checkboxes are a simple shortcut to achieving that motivation for many. They don't work for me, my experience is similar to yours.

I've realised that if I can find something rewarding to enthuse me, then I can tackle a task. And that reward needs to outweigh distractions, it's no good saying I can have two marshmallows later, I'll take one now thanks. So I try to focus on any aspect of a task that I might find rewarding in the present moment, and if I'm lucky it will push competing distractions aside enough that I can get started.

Every. Damn. Course. That I've ever attended has pointed to 'check the boxes' rather than 'find your motivation'. Checking boxes feels like walling myself into a tomb (see other comments in this thread). It's beyond frustrating.