Chisel MTB to gravel conversion

I’m trying to convert my singlespeed Specialized Chisel boost frame from a MTB setup into a gravel setup temporarily by adding gears and swapping cranks/chainring.

The problem I’m running into is trying to get a 40T ring on without rubbing the chainstay. I’m running an old GXP BB with 2.5mm spacer and Truvativ crank currently + 32T ring. Do I need to swap to a DUB BB to get more crank options?