AC2200 Triband RBK20W-100NAS - Looking for extender options

Hi All!

My apologies if this has previously been addressed, but I did not find an answer in the community:

I have a non-nighthawk RBS20/ AC2200 (purchased from best buy with the model # RBK20W-100NAS) 2 piece kit which came with the wallplug adapter in which I am looking to expand to include more extenders. As it seems the RBS20/ AC2200 line has been discontinued, what model(s) of extenders would be compatible with this setup?

The closest option I can see is the AC3000, RBS50, but being that it is faster, wanted to ask the above before purchasing.

Thank you in advance for the insight!