There is evidence of the opposite: graph singular isogeny mumbo jumbo algorithm was proven to be easily broken on an ordinary computer.
Hybrid encryption is as simple as running one encryption and then the other. Problem is mostly that post quantum keys are large.
Am I missing something fundamental here?
If Algo-A and Algo-B both rely on "factoring big numbers is hard!" then once the Quantumpocalypse occurs, breaking Algo-B(Algo-A(plaintext)) is no harder than asking ChatGPT 99.5 to add an extra step in your vibe coded cracking engine's frontend, such that it now does B_breaker < cyphertext | A_breaker >> plaintext.lol or whatever the equivalent is for the fashionable language of the that future day.