The problem is harder if we demand flexible fabric. That isn't how gas masks are done. With a canister filter, all sorts of options become possible. We could use sintered glass, ceramic, or metal. We might be able to use aerogel, diatomaceous earth, or metal foam. We could even go electronic, with a UV light.

Filters with greater air flow resistance can be used if we add a blower. Remember that the virus can enter via eyes. Eyes need protection. Eyes also need air, and it can't be humid or the protection will fog up. For this too, a blower would help.