I've seen DRF did that. Not sure if that is not possible for normal accounts.
Which of these projects is more likely, relative to the other in its pair, to be targeted by users whose expectations are presented disrespectfully by whatever means (let's assume email) the users can discover?
1a) A project that has recent commits, but has pull requests and issues disabled.
1b) That exact same project, with the banner "This repository was archived by the owner" shown on all pages and objects within it.
2a) A project that left a work in progress unfinished six months ago, but has pull requests and issues disabled.
2b) That exact same project, with the banner "This repository was archived by the owner [six months ago]" shown on all pages and objects within it.
As one can reasonably predict, archiving when I'm not actively pushing commits turns out to be an effective way to stem the tide of jerks who otherwise pick a fight by email/irc / discord/forum / blah/blah / etc., in hopes of persuading me to commit further resources to their unpaid benefit or to finish something I don't care to work on finishing right now / this week/month / quarter/semester / year/decade / ever. It's archived, so clearly it'll never be finished, which helps enforce an appropriate calibration of expectations upon those desiring the outcome — and if I someday finish it, hooray, but no one has any plausible way to justify any expectations to the contrary, no matter how hard they wish otherwise. Thus why I recommend using archiving to remove the social pressure component of working in public on GitHub.
Of course, if you have a better solution than you've offered so far here, I'm certainly willing to consider it.
If you archive it, then sure user's are less likely to send you disrespectful messages by whatever means (assuming they can find such means), but they are also less likely to use it, because you have basically said "this project is abandoned". Which if you don't want users at all, I guess that's fine, but then I'm curious why you bothered to publish it publicly at all.
There are only maybe a few thousand people at most worldwide who could benefit from what I’m doing, and only 1% of them might actually go looking for this. Can you imagine working as an open source maintainer on a project with a hard cap on audience size of a hundred people? Seems fine to me; I’m one of those hundred, after all :)
You will hear only crickets.
Adding the slightest friction, and making potential drama 1:1 only, demotivates most people.
You might miss out on an occasional good feedback, though.
Further downside is that your project will have a harder time becoming popular, and being popular is secretly (or not so secretly) the motivation for many in open source.
Will be a lot more honest though.