YN is about the last place for medical advice of any sort, especially around ADHD. Just look at the comments, A LOT of weirdos getting out of their basements. Or anything covid related.
Being mildly competent in tech doesn't translate into medicine, but you have a loooot of inflated egos around here.
In some cases they can make things worse, it's worth remembering that query optimizer looks not only on indexes, but also on statistics and estimated operation costs. If your statistics are out of date and your criteria are not specific enough (e.g. they match 80% rows), then an index is going to slow the query down. It needs to traverse the index to get the row IDs, fetch all the blocks containing them, read those, filter out irrelevant rows. It's probably going to be faster with a pure full table scan (due to linear reads).
The guy mentioned he has social anxiety and autism, the likelihood of him being able to improve his soft skills meaningfully without a long (and costly) therapy is unlikely to say the least.
I use lists as one of the coping mechanisms for ADHD, depending on the day it's anywhere between 20 and 100 of various granularity depending on what I'm doing and how I feel the given day.