Its not scary flush. Ac on the board and you have Qc. OTR i go for allin not small bet. Its microstake player can easly overplay this hand but when you bet half pot and get raised its generally unbluffed line. I think you can fold. If vil agro fish i can call river too.

Even at NL2 players cbet 1/3 pot? Woah the game has improved a lot even at micros.

Anyway, shove river, you are betting a polarized range that benefits from betting bigger amounts

As others have said, shoving river yourself would be simpler and shouldn't affect his calling range. It also saves you this weird spot where he can min X/shove. I'd still call though as he can do this with worse Ax once in a while as likely a weaker player