why isn't there a forum for the M0 Pro?
Because it SHOULD be the same as the Zero, except for the pinswap (and THAT should be handled transparently, and only bother people who use "direct port IO")
PWM doesn't work with the M0 Pro bootloader
This is the first that I've heard that PWM has problems on the M0 Pro. Even if true, that should have nothing to do with the bootloader! Could you provide the usual "I think I found a bug" details, like your code, which pins, which version of the IDE and core you're using, and so on? The SAMD processors have two kinds of timers, and there are some differences between the variant.cpp files WRT Timers/PWM that I don't understand, so this COULD be a real bug caused by "version skew."