It can be done, but this is a seriously bad idea. If something is causing the site to crash when core or plugin updates happen, you need to solve the issue that is causing the problem, not rollback updates! If it’s a commercial site with value in any way, it’s pretty insane to setup a policy to keep updates rolled back. I suppose there could be a research reason or testing reason to do this, but I’m baffled by anyone doing this on a forward facing production site. DON’T DO THIS. KEEP YOUR SITE UPDATED.