I'm working on an project to solve this type of issue. What we do is put test servers throughout your provider's network and then provide a browser frontend tha

I'm working on an project to solve this type of issue. What we do is put test servers throughout your provider's network and then provide a browser frontend that will test your connection (throughput+latency) to each point on your provider's network on your way out to the Internet. I would love to come up with a way to do this without requiring the provider to install anything, but so far that doesn't seem technically feasible. One of the main problems is that so much of last mile networks is now layer 2, so traceroutes aren't particularly helpful at narrowing down the network segment causing the problem. The good news is that many of the smaller providers (where they exist - maybe your LTE provider is one?) are very excited about adding something like this to their network. Where the incumbents would rather just hide problems from you to keep you locked in, the smaller providers are very motivated to keep you on their network. They're often overworked and resource strapped - so a system that will help them narrow down the source of network problems and reduce truck rolls is usually very exciting to them.