I’m 57. I have tasks that have been on my list for years!!!
A tip that I picked up when I realised I couldn’t get started was to choose the three tasks that were the most important but you didn’t really want to do and then don’t do any others that week until you completed them. This has really helped me get the boring tasks done.
I also find that some meds for me allow for better quality sleep. Vyvanse was great for me at first but then I found that I was actually hyper focussing as I wasn’t getting any deep sleep so it affected my cortisol levels.
As the previous poster says everyone is different. Good luck