In other words if this PR is merged and if you run the next version of bitcoin core you will no longer be able to choose which OP_RETURN size you want to relay (that choice should be yours to make), and instead you will be forced to use what the default setting is!
It won't be merged.
In fact things like this are the reasons why I've argued for the benefits of having a strong alternative implementation of the Bitcoin protocol to be used instead of core...
But jpeggers wouldn't have the prestige of having their jpeg on Bitcoin. Ordinals-type inscriptions are already being done on a dozen different chains and people still would prefer to do it on Bitcoin (when fees are cheap enough).
At some point when the core devs keep refusing to fix exploits like what allows the Ordinals Attack to take place and then limit users' ability to set their own standard rules, the benefits of having an alternative implementation outweighs the disadvantages of it...
BTC reached all-time highs in terms of price, transactions per day & hash rate after the introduction of Ordinals. Perhaps the wisest move was doing nothing at all, as the "Ordinals attack" seems to have been the worst attack on Bitcoin of all-time.