Wireless Joint

I would flash back to the old firmware to verify if newer firmware is actually the problem via this method https://wirelessjoint.com/viewtopic.php?f=12&t=5

Have you tried using the router's sim card in your phone and compare speed to your phone sim and see if everything is OK? Unless it's not a nano sim and you can't fit it into your phone's sim slot. What kind of modem is it? Your power adapter should be fine if it has been working for awhile.

It seems to me like it's a sim card issue if suddenly you get frequent disconnections. Could you put your phone's T-Mobile sim in the router and see if it acts the same?

That's to be expected because your phone's modem is a lot better than the MC7455. Now put your phone's own sim into the router and see if you still get the disconnections if possible.

LilAkka wrote: Sat Aug 08, 2020 6:07 pm I enabled connection monitoring, I can't recall if the TTL is setup that way. How do I check that?

Make sure you add tracking ip like 8.8.8.8 for the script to ping in the settings page.

LilAkka wrote: Sat Aug 08, 2020 6:33 pm Ok, it's currently set to 65 actually.

Then I would leave it as it is.

Network->Firewall->Custom Firewall
For T-Mobile I believe it's TTL 64

Possibly the pings the connection monitor is doing is also keeping your connection alive and preventing the modem from going into low-power mode...?