Both my kids have minecraft on switch. My daughter can load in but it takes upwards of ten minutes to load and then sometimes freezes up requiring a reboot again, my son cannot load in at all and was taking 20 - 30 mins before it failed to load anymore. I'm paying for realms plus and they are barely able to use it, my daughter has spent some of her own money on minecoins.  I tried removing all their custom wolds saved to their account, I tried clearing all kinds of save data and caches and other things suggested in similar posts but nothing has worked so far. 

This has been going on for about 3-4 months

Please can we resolve this. They love minecraft.