I don’t really want to run a mailing list, I just want to archive email and make it browseable and searchable via web browser.

Is HyperKitty an appropriate solution, for this use-case?

No, sorry but I don't think HyperKitty will fit your use-case. It's integrated with Mailman in many ways (it won't even run with Mailman 2.1).
Good luck with your research.