MR80 MESH interfere with devices joining the network or when on my VOIP Mitel Connect app

Thanks for your assistance, I really appreciate it.  I know enough to be dangerous and will answer as best i can if you need more i will find it...

1. what modem/gateway do you have? 

As provided by my ISP, I don't really have any spec. Is there somewhere I can find that detail?

2. what speeds do you pay for upload/download (both)?

50/50 comes in at down 51.93/up50.51 nothing crazy but adequate for Gotomypc and Mitel Connect

3. what actual mitel device is it? 

There is no physical device it's an application "Mitel Connect" I use a Jabra blue tooth headset with the application. sometimes i use it on my apple I-Phone 12 or on my Windows PC.  My issue is in my rural location cell service is not so great, so the cell phone is also on the wifi to improve the signal via wifi.so i really can't get away from using the router for both devices. I have considered a cell signal booster but that uses the router as well.

4. is it connected with ethernet or over wireless?

The connection for my PC, which I run this all on is a direct connect only 10' away.