and is yet to 3 bet over 20 hands.

This 3-bet is celarly never a bluff and could even be a range as tight as [QQ-AA AK.]
Unlikely to be a bluff, but I think assigning such a tight range based on 20 hands is silly. It just seems like you're calling a 3bet OOP and hoping to see an A on the flop so you can feel justified in folding.

On the flop, I wouldn't be surprised if he's raising his entire range here. It's a $1 donkbet into $7, my standard response to small donkbets is always to raise them, they fold a billion percent of the time.

I dunno, straight up, you're better at this than I am, but I think you're reading way too far into a twenty hand sample to make this kinda cautious play.

Discussion, ho!