There was plenty of support before AskUbuntu, and those venues are still active.
UbuntuForums and IRC were both much busier before AskUbuntu, and both can reasonably be expected to handle increased load again, if needed. Recall that the Ubuntu IRC Council migrated from Freenode to Libera back around 2019.
The Ubuntu Wiki hollowed out and became a ghost town after AskUbuntu grew popular. But it's still there, and still available. There has been low-level buzz for years about shutting it down due to lack of use...but it's still there anyway. Ubuntu Members still have edit permission --yet another good reason for Ubuntu membership-- and it can spin back up rapidly if folks find a need to use it.
Ubuntu Discourse is specifically NOT for technical support, but it's the home for pages that we should be linking to: Team-produced documentation (replacing their Wiki docs), Ubuntu Tutorials (tutorials.ubuntu.com), updates and news and announcements, discussion and collaboration threads, etc.
And all that is currently in existence and running right now. No planning or preparation needed beyond new login/passwords for some folks. Plenty of alternatives with plenty of capacity.
That's before we get to the unofficial venues that already exist: Reddit, Codictat Linux, Discord, etc.