I’m wondering that I am unable to see how precisely BIP 0341 forbids v1+ segwit from utilizing bech32.
BIP341 has nothing to do with this; it specifies consensus validation guidelines, not deal with encoding.
BIP350 nevertheless specifies that Bech32m should be used for v1+ segwit, and Bech32 for v0 segwit. The older BIP173 specified that each one witness outputs (v0 and v1+) use Bech32.
Does consensus enable combining v1+ segwit applications with the bech32 format?
So far as consensus guidelines are involved, addresses don’t exist (solely scripts do). Conversion from/to addresses is one thing finished by wallets (and different user-facing software program), and thus if such software program follows BIP350, they’d use Bech32m for v1+ segwit outputs.
Previous pre-BIP350 software program nevertheless may use Bech32 for such outputs, that means such software program will not settle for addresses created by BIP350-compliant wallets. That is deliberate (from BIP350):
Experiments by Taproot proponents had proven that hardly any wallets and companies supported sending to greater segregated witness output variations, so little is misplaced by breaking forward-compatibility. Moreover, these experiments recognized instances through which segregated witness implementations would have brought on wallets to burn funds when sending to model 1 addresses. In case it’s nonetheless in use, the chosen method will stop such software program from destroying funds when trying to ship to a Bech32m deal with.
Does consensus enable combining v0 segwit applications with the bech32m format?
Once more unrelated to consensus, however BIP350 doesn’t enable this (and neither does BIP173).