IOS 16.5 ipad update - so many wonky mail issues

Where do I start? Email Messages don’t load, it takes a long, long time, the iPad keeps checking for mail - forever - then when they finally do load, I can read them, then delete them or move them, but they quickly return to the email inbox as unread messages - again and again. In frustration, I deleted the emails from my iMac desktop, then plugged the iPad into the iMac thinking it would update itself to whatever was showing on the iMac, but alas, it did not! There seems to be syncing issues - either with connecting to WiFi and updating, or connecting directly to my iMac (my main PC). We have 8 iPad Pros as we use them for playing music in our band and this is so tedious and frustrating. I’ve just about had it with tech and it’s constant updates and constant glitches. Needless to say, we’ll never own this many devices again - way too much time spent troubleshooting. So much for future sales Apple. The iPad Pros are different generations, bought at different times, and if someone could tell me where to find the “generation” under “Setting-General-About” - I could answer that question.