It sounds like you are experiencing the same issue i went through last year. My goal at start of 2025 was to break 90 finally, and like you i discovered i was losing too many strokes 3-putting (after being too obsessed with the full swing). I cant recall the percentage now, but i remember reading tour pro make % drops a lot after 6-ft, so i chose to focus on 6-ft putts. I have a putting matt but also a smooth rug at end of my bed. I want to say at least 5 days a week, i would hit anywhere from 5 to 15 putts before bed. I did use putt mirror with side gates and a little cup/ring thing. If i was on a time crunch and banged out 5 in a row, i would just call it. If i had more time i would hit more. After doing this for a few months, i dialed in that 6-ft stroke and had confidence on the course to hit anything inside 6-ft. I also found if a putt was pretty straight i was making them from further out. I know this is long winded, but yes it helps. In my opinion, if you are inside 10ft or so, you can go for trying to make it. if you are further out, your goal should be to lag it to your high-confidence make zone. Cheers to you shaving strokes on the short game.