1.16.21 patch still doesn't work

I have two Nintendo Switches - both were crashing with the 1.16.20 update and neither device could be used with Minecraft which created endless frustration in our family. I was very relieved to see a patch and downloaded it. Now both Switches are still logging out and now they can't play with other friends on iOS or other platforms. Extremely disappointing and many hours have been spent trying to solve this problem. We bought the Nintendo Switches just playing Minecraft with friends and it is extremely upsetting for my children. 
please help.