I used to have all sorts of issues with my teeth, and ended up with 2 root canals, and crowns, and had 1 of them go bad. Ended up with an implanted tooth. Yikes.
Learned later about how cavities work and figured out the best routine for my teeth - floss and then brush (Philips electric toothbrush) every morning. Brush and then fluoride rinse every night. I always floss/brush before breakfast, and wait at least 30 min after dinner to brush/fluoride rinse.
I haven’t even had a cavity in 5+years, and my dentist always says I don’t even have any plaque to scrape off - “you have good dental hygiene, and I don’t say that very often”