Would you want to face perjury charges from a DC judge and jury based on saying something you or I would think was perfectly true. God’s truth is not an adequate defense in all human jurisdictions. Speech within the context of official Rep/Senator business is by its nature political and in a representative democracy it is not just the speech of them personally but the delegated speech of their constituents. It deserves extra strong protection. If they lie too much the check is for us to vote them out or perhaps for their mates to expel them. No court should interfere with conduct there because of separation of powers. To earn that requires the non-trivial process of winning their seat. SCOTUS has somewhat extended that protection as delegated to their staff doing their official duties. But it isn’t unlimited. As a non-lawyer I can’t claim to know all the precise limits. But if they were to slander you when grocery shopping back home I don’t think they’d be protected. If they lied under oath in court for a divorce suite I don’t think they’d be protected. Lying under oath to Congress is infrequently prosecuted, and currently only under a double standard, but IIRC the witnesses to the J6 kangaroo court were sworn, the J6 committee members were not sworn beyond the general Congressional oaths taken when seated. I don’t think they qualify for perjury because they weren’t speaking under oath in the sense that requires. However, those morally guilty in our minds spread their filth widely and may have thus incurred legal exposure beyond the limits of the speech and debate clause. By all means look for that as an opportunity for slander or libel charges, rather than perjury ones.
Not just that, but simply to be tied up in court instead of continuing the debate. The process is the punishment.