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

Definitely more realistic for you than for the typical 50 year old player rated 600 who wants to become a GM in 6 months.
I have charted the development of chess masters in my city, many of whom started competitive chess in high school.
Yes, NM is a realistic goal. Most of the masters I have studied reach Class A (1800-1999) in one to two years, Expert (2000-2199) in two to four years, and Master (2200+) in three to seven years.
One thing to remember is that the NM title in USCF is based on OTB chess played at classical time controls. Online rapid and blitz ratings are fairly meaningless and are often inflated relative to real ratings. So, if the NM title is your goal, I would recommend playing in OTB tournaments. Also, be aware that many coaches recommend that developing juniors NOT play blitz and bullet, because this teaches a superficial style that interferes with serious chess development.
Good luck.
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.