fraksken

messing with html sounds very worrying to me. is that on https connections to any site they do not control? Do you have an isp application installed?

I’m using DAVx which is available on F-droid. syncs contacts and calendar with nextcloud.

That is literally fucked. There are some scenario’s where I can imagine an ISP wanting to force wireless on. a mesh network for their customers sounds like the most straightforward reason. if you cannot replace the router, faraday the shit out of it. put your own router behind the isp router and don’t forget to change the MAC address of the router (isp will probably block any 3rd party router macs on the network. seen it before)