Is National Master in 2-3 years a realistic goal for me?

Then you also need to have a very good repertoire, it’s possible, but completely up to how much time you are going spend studying chess
If you feel that it is worth all the time and effort then go for it
Do you plan to grind rapid again? You’ve been sitting at 2005 for a while now.
Probably not, I play some blitz but I barely enjoy that. My original goal was 2,000 and I hit it I have nothing else I wish to achieve.
That’s fair, 2000 is a great goal. As long as you had fun, elo doesn’t really matter much.