'qa-topic-tip' Ember is not defined error

Info on the Ember upgrade can be found here: Preparing for Discourse's upgrade to Ember 5

Have you tried loading your site in safe mode? My guess would be that you have a theme installed which defines a component called ‘qa-topic-tip’.

If you can share a screenshot of the error message and backtrace that would also be useful. The copy/pasted versions of browser console logs are missing a lot of information.

qa-topic-tip is from the old Pavilion discourse-question-answer plugin. That plugin is no longer maintained, so you should remove it from your app.yml file and do a full rebuild.