Either house of Congress can certainly remove a member from the floor for disorderly conduct. If, say, a member attempted to attend in the nude, the Sargent-at-arms could and probably would remove the member and prevent the member from returning until the member complied with the rules. Ar one time, I believe, Congress required that members wear a necktie while on the floor, and this rule would similarly have been enforced. (I do not know if that rules is still in effect.) A rule requiring wearing a mask, if one were passed, would similarly be enforceable. As a member could resume full participation at any time by complying with the rules, there would be no impact on the rights of citizens to be represented.
An elected member of congress could choose never or only rarely to attend sessions. The only remedy would be to elect someone else when the member's term expires, or for a 2/3rds vote to expel the member, although the Sargent-at-arms does have the authority, when so instructed by the Speaker of the House or the President of the Senate, to arrest absent members and bring them before the bar of the house, a power which is used to obtain a quorum, as mentioned in Article I Section 5 of the US Constitution, which reads:
... a Majority of each [House] shall constitute a Quorum to do Business; but a smaller Number may adjourn from day to day, and may be authorized to compel the Attendance of absent Members, in such Manner, and under such Penalties as each House may provide.
All this is speculative until and unless a House of Congress adopts a rule mandating the wearing of masks in its chamber, or in the Capitol.