No

No, that is not what will happen. All mined blocks become invalid. So all transactions in them become unmined. Unless they happen to be mined in the other chain too. Perfect time for a a large double spend... Even considering an approach that might cause a reorg is hostile to bitcoin and bitcoiners.

That's not how that works. Nothing gets "unmined" The scenario ODELL is trying to describe is if no one supports BIP110 that chain stops because of so many invalid transactions on the main chain then miners switch completely to BIP110 and mine literally tens of thousands of blocks faster than everyone else can mine a single block on the main chain. I hope I don't have to describe how improbable that outcome is.

Only if the miners on both sides mine at the same speed and there are no RBF transactions. And miners chose the same txes.

A chain split will create two chains, like when Bitcoin Cash happened and lost the split. It became a minority chain no ones care about; anyway there were funds loss because at first transactions would happen on both chains at once and stuff like that, it was a messy process & we definitely don't need that now.

Agreed that this is not ideal and its a risk on bitcoin stability (assuming the BIP-110 fork is initially a minority chain), but in your opinion, what should we do about UTXO bloat (which is a risk on decentralization) ?