Yes, you can still turn off validation, at least on Java edition - you can even host your own validation server via drasl and similar, but that requires the server to have config options set to use your custom auth (and probably skin) server, and your client to have the libauthinjector mod installed.

Works great as an alternative to whitelisting IP’s to play with friends, and means you can’t have your Minecraft account deleted because you swore on your privately hosted server and a friend hit the report button.