Assummng you are running even modest quality tires, you can definitely go lower and will experience benefits with no loss in speed unless you are on something litterally as smooth as pavement.

However, at your weight, and with 2.1” tires, 20-25 seems too low, particularly in the rear. You might not get pinch flats, but you could definitely get rim strikes.

I weigh 175, run 2.3” tubeless, and have settled on 23 front, 27 rear. Other people might even go a bit lower.

In your case I would definitely try going lower. I would try something like 28/33 F/R. I think if you give it some time, you will likely find that works better on dirt. If so, try going a little lower bit by bit. At some point you might feel rim strikes or it may feel squirmy in corners. Then you know you went too low.

Also, you can pretty much always run lower pressure in the front. Not as much weight on the front end.

Interested to know what you find.