2. enamel is far too strong to be abraded by the brush, what does get abraded is the dentin (the yellowish part closer to your gums, that's why sometimes you can see small dent-like abrasions there) so try to focus on brushing softly in those areas. A good idea is to use soft bristles

All you do is good and you're probably already doing 95% of what can be done, the other risk factors are smoking, female hormones, stress and diet. If you are not stressed, don't smoke, are male and eat mostly plant-based whole foods you can't do much more than that