Pedantic...

Chain split, no one has perfect knowledge so for a bit 2 different chains of the same length but different blocks exist. Eventually 1 chain takes the lead and everyone moves to the longer chain. There will be 1 chain again eventually after a split. The blocks that were mined on the abandoned chain are called orphan blocks. After the merge back into a single chain it is like the orphans never happened.

Chain fork. This is where Litecoin, BSV, BCH and other shitcoins come from. Because block validation rules are different these can never merge back together.

Knots is not a risk of a chain fork given current stated ideology and programming. It is a risk of a chain split.

Does a split matter? Say a big miner like Foundry, 35% of blocks, and a tiny miner like ocean, 1% of blocks, both hit blocks at the same time and split. Which block will most likely be orphaned? During the split each miner follows the chain they heard about first. Well foundry has a guaranteed 35% of all hash following their block. That means ocean is most likely to get orphaned. An orphaned block means I as an ocean miner don't get paid for my hash.

So I'm incentivized to mine with the big pool because fewer orphan blocks means I get paid more. Downside is now foundry gets even bigger and controls mining even more than their current 35%.