Allow the repeater to be locked if it powered from the side.

Is there a vanilla equivalent to this feature that I'm not thinking of?

Of course! Look under https://minecraft.gamepedia.com/Redstone_Repeater signal locking

Ah. I feel silly now. lol. So, it should lock on side input from a repeater or comparator.

Why silly? You make a nice mod and did not have one thing on the screen.
Definitely yes. This is how the locking of a repeater works.
A very important functionality, especially if you work in the 2d area.

Released

I love it

T-Latch Circuit