I'm pretty new to understanding about my undiagnosed adhd, but I figured performing a dopamine detox from bad sources, and maintaining some dopamine from healthy sources like meditation and exercise help me sort a little bit.
I still have problems with procrastination (much less tho) or that motivation bridge, I use pomodoro technique and proper breaks to rest my mind from the work does help me most of the time.
The most important thing is to journal or plan out your day, setting your goals and achieve them throughout the day with methods given above. It's almost creating an artificial brain which tells you what you should do.
I kinda over-elaborated it but that's something i can't help :')
This is where I am, and I hope this somewhat helps. More power to you.