layer 3 that are trustless won't need face that problem.
The key layer 3 that are trustless to a certain degree are Statechains and Channel factory(depending the design).
Liquid and RSK are also layer 3 but they are not that trustless or are to a lesser degree ie RSK. RSK is more open than Liquid but still has a Federation which intersting control but doesn't control the bitcoin the same time. RSK does plan to get rid of the Federation but it depends if main net will get a soft fork peg