I think this is unlikely. Mac gamers need Unreal more than games developed using Unreal need Mac users. Mac is an incredibly niche market for games - they're not going to rewrite their game using a different engine to run on Mac, and Apple knows that.
Of course, Apple could decide they don't give a shit about native Mac games, why don't you play our iOS games, but that just seems petty.
I think it's possible to make persuasive argument that this already took place around the time that they killed OpenGL support and/or refused to allow Vulkan support. Requiring a proprietary API that only works on a tiny subset of gaming devices* seems like they've already made their position on this topic very clear.
* I'm excluding mobile devices here since mobile games were called out as a different market in the parent comment.
The relief to which Apple is entitled is that to which Epic Games stipulated in the event that the Court found it liable for breach of contract, namely:
(1) damages in an amount equal to (i) 30% of the $12,167,719 in revenue Epic Games collected from users in the Fortnite app on iOS through Epic Direct Payment between August and October 2020, plus (ii) 30% of any such revenue Epic Games collected from November 1, 2020 through the date of judgment; and
(2) a declaration that (i) Apple’s termination of the DPLA and the related agreements between Epic Games and Apple was valid, lawful, and enforceable, and (ii) Apple has the contractual right to terminate its DPLA with any or all of Epic Games’ wholly owned subsidiaries, affiliates, and/or other entities under Epic Games’ control at any time and at Apple's sole discretion.
This may very well kill Epic's Unreal Engine business (at least on Apple platforms) if they no longer have the necessary licenses to use Apple's developer tools.