Maybe try starting a routine to wake them after the go to bed to use the toilet or to try to It might help their bodies know to pee when awake ?
My mother tells me she use to sit me on the toilet before she went to bed herself even if I was barely awake, and tickle my lower back and it would make me pee
You’re not alone! My 5 year old has recently started wetting his bed again. It’s upsetting and frustrating 😭