self-employed participants vs. mandatory automatic enrollment

This seems obvious to me, but I want to be sure that I'm on good footing here (or at least as much as possible).

S/E participants have their compensation determined after the end of the year, but they need to make a deferral election by the end of the year.  It seems to me that if they are in a plan that is subject to mandatory automatic enrollment, then if they don't complete a deferral election of some kind by 12/31/xx, then they are subject to the automatic enrollment percentage and that is they only deferral they can do for the year.  This is mostly true for a new partner who joins the plan - when they first become eligible, they may not necessarily need to complete a deferral election form as soon as they become eligible (though it would be smart if they did), but definitely something should be in place before the end of the year.

If they choose to defer during the year, then obviously it must be pursuant to a written election form, and therefore they are out of the mandatory automatic enrollment rules.  So that's fine.

All the usual caveats about evergreen elections vs. ones that are specific to the current plan year and wording them to allow the maximum each year, etc. apply.

Hmmm.  If a deferral election form says "I want to defer $X for 2025", what about 2026?  Is there no deferral election, and therefore they are teetering on being subject to the mandatory rules again (until they make a new election)?

Thanks.