multi-tenancy based on linux? shouldn’t be a real problem.
but… this seems to be a professional usecase here. and you are asking your question on the community (aka home-driven) forum… so of course there could be some valid answers here as well… but if you want a reliable answer and maybe even a solution try to talk to nextcloud inc, directly and let them offer you a quote for professional support. for professionals.
that would be considered very fair.
thank you.