On Android:

1. your profile icon (bottom right) > hamburger menu (top right) > Notifications > Posts, stories, and comments > turn off ‘Posts suggested for you’ and ‘Notes’

2. on the same screen, set ‘First posts and stories’ to ‘From people I follow’

3. back out to Notifications > Live and reels > turn off ‘Recently uploaded reels’ and ‘Reels suggested for you’

This works for me, but if you’re still getting notifications you don’t want, you’ll have to figure out what category/type they fall under and turn that off.