I hate that this is a thing. I'm dealing with a similar potential issue on Charter Spectrum right now. Specifically it's an issue that's called out here https://blog.cloudflare.com/ip-fragmentation-is-broken/ (failing the IPv4 fragmentation test http://icmpcheck.popcount.org/ ).
How on earth is one supposed to get past the front-line tech support in 2023?
Separating the last mile infrastructure from the ISP can make it possible to have natural monopoly for everybody's last miles, but widespread competition for ISPs. That might be really hard to pull off in the US but I think it'd be worth striving for.
Or even better, the model we have in France. The last mile is a monopoly for a limited time only (2-3 years). So if you build a connection to some place that didn't have one, you can profit off exclusivity for some time, and are incentivised to be good to the consumers because they can switch, but will probably ony do so if you're shit/too expensive.