But more importantly:
1. No, quantum computers that big don't exist.
2. If they are somewhat practical, you really want perfect forward secrecy so they at least have to break a classically hard problem _every time_, which is unlikely with home-rolled RSA systems.
3. If you do care about post-quantum KEX (because your information needs to be secret for longer than you can count on quantum computers not being practical), we have faster alternatives, like SIDH.