It could be the service. The source. Or you. Have you checked their support to see if they can refresh it and fix the channels? Is there a discord to see if other people are having those issues?

most IPTV providers try to force FHD (1080p) when a simple SD (576p) will suffice for most, i have shitty net/ISP in a 3rd world country, i'd be happy with a damn 480p but those are harder to get :(, even harder is the more modern x265 iptv providers..