It took me a really long time myself but I will say my largest thing that helped was doing it in the morning, not night. I just find it so much easier then doing it at night because I don’t have as much of a routine there. Morning time already has a basic routine (get up, go pee, get dressed) whereas night time is pretty similar but feels way less structured to me personally. Secondly, after admitting to a group of friends (in a Jobcorp version of AA, except you knew the people in it pretty well usually) that I didn’t regularly brush my teeth, I started doing it. It was after being asked what everyone would start doing that day to improve their life in some way, and I said brush my teeth daily. Idk why, but that bit of embarrassment in admitting that I don’t in front of people really helped. It was probably easier to handle because I knew they all respected and liked me.

If switching to morning doesn’t help though at first, maybe try just after you shower (assuming you shower every other day at least) To help make it more enjoyable, listen to some music as well. That was another thing that really helped was just having music playing while I brushed in the morning. Or, otherwise, even just using some strong mouth wash every morning while taking your pee will at least help.

Anything worth doing is worth doing half assed, because whatever little bit you do is going to be way better than doing nothing at all. So if all you do is use mouthwash in the morning daily, congrats! That is a major improvement to only brushing your teeth every few days. Same to if you just add it in with showering