Is it true that this type of update could affect Bitcoin's decentralization?

If there are transactions that regularly get mined but do not get relayed, we are incentivizing the users that are invested in such transactions to run less strict mempool policies and mining pools to build out tooling for direct submissions. The largest mining pools have the most resources to build out such tooling and are most likely to get direct submissions. Our choice is to let the largest mining pools benefit disproportionally or to make these transaction fees available to any node that wants to build a block template. In so far, yes, this change could slightly improve decentralization by mitigating some centralization pressure. Other than that, I don’t see how it would affect decentralization, and especially claims that it would have a negative effect seem to be based in hyperbole.