OxygenOS: Large number of SMS Messages to Group??

Hi there, I am currently having a bit of an urgent dilemma.

Basically, I'm wanting to send messages to a group of people, however every time I get this message propping up that there is a large number of messages.

Additionally, how on earth are you even meant to send group messages to people that you have grouped under the same group in contacts??? I'm lost with this new GUI.

Someone PLEASE save me. :(

Receiving messages late / out of order on AT&T US

Just got a new z5c - I'm in the US on AT&T. This didn't seem to be a problem until last night, but now I'm having messages take between 5 minutes and 2 hours to come into my phone. People are still getting my sent messages instantly. Never experienced this problem on my old phone (2013 Moto X using same sim card), so I'm guessing it's not the carrier but the phone itself.

Also, restarting my phone seems to cause all the backed up messages to come in at once. Really annoying problem, wondering if anyone can help.

I switched my sim card back to my old phone and a bunch of messages came flooding in. Asked friends to test texting me with sim card in each phone - texts came instantly on old phone and way delayed on z5c. Already disabled iMessage. I've tried using Textra, the messenger app that comes with the phone, and Google messaging and all have the same outcome.

Receiving messages late / out of order on AT&T US

Just got a new z5 - I'm in the US on AT&T. This didn't seem to be a problem until last night, but now I'm having messages take between 5 minutes and 2 hours to come into my phone. People are still getting my sent messages instantly. Never experienced this problem on my old phone (2013 Moto X using same sim card), so I'm guessing it's not the carrier but the phone itself.

Also, restarting my phone seems to cause all the backed up messages to come in at once. Really annoying problem, wondering if anyone can help.

I switched my sim card back to my old phone and a bunch of messages came flooding in. Asked friends to test texting me with sim card in each phone - texts came instantly on old phone and way delayed on z5. Already disabled iMessage. I've tried using Textra, the messenger app that comes with the phone, and Google messaging and all have the same outcome.

Blocking Incoming Text Messages for Specific Time Period

I would like to be able to block all incoming text messages for a specific time each day (ie, 8:00 pm to 8:00 am). I understand how to do this with incoming calls, but is there a way to do this with text messages? An added bonus would be the ability to send an automatic response during this time.

Thanks.

Why does Samsung Pay need access to make phone calls and read/send text messages?

Not that I particularly care but I think it's a little strange that this app in particular needs access to all of this stuff. Am I downloading the correct app and/or are there "fake" samsung pay apps on the play store I need to watch out for?

Edit: Guess this is a moot point for now - only have Wells Fargo, none of the other banks approved to work.