Article 50 no longer applies to the UK. It ceased to apply the moment we left the EU on 31 January 2020 at 11pm.
So no matter how badly the Brexit negotiations go, there's no "remain" option any more.
Brexit is governed by facts. The treaties and trade agreements we shredded on leaving the EU. Geography. The Withdrawal Agreement, etc.
All the facts still point to Brexit being a disaster.
What we should continue to do is hold a magnifying glass to reality.