Internet problems

So I've been having intermittent internet issues for about a month and consistently unusable internet for about a week.

I'll be getting my full speed down and up with low latency, then suddenly after anywhere from 30 minutes to an hour I'll start getting crazy inbound packet loss. If I'm on Discord while it's happening everyone else will sound robotic and nothing will load (or will load very slowly), but for them I sound normal. Sometimes I can get a speedtest to run and I'll have almost nothing for download but my full upload speed. The strange thing is if I restart my modem the problem will literally vanish, every time. But the issue will ALWAYS come back after some time.

I've obviously had my ISP send people out (for context, I live in an apartment with 12 units, this may be pertinent later), and they've never been able to give me a resolution to the problem or even positively isolate the issue. I had one Tech leave and call someone else in to finish the job because quote: "I'm tired of chasing ghosts in this building" (which I found hilarious more than anything). I'm assuming there's a lot going on in the networking stuff in the basement because they've been down there many times and for many hours in total trying to track down the problem.

Now fast forward to a few days ago, the last time I had someone out to look at it. This time around was different in that the tech actually seemed pretty positive on what the issue was. According to him the signal at the wall (coaxial) in my unit was clearly bad, but downstairs at the other end of that cable, the signal is good. So he was pretty certain the problem is actually the cable in the wall, which they unfortunately can't do anything with so I was referred to my landlord to resolve the issue.

Now my question is; does that sound plausible? I am by no means an expert but from what I've heard, these coaxial cables very rarely go bad and the issue usually lies in the splitters (which I assume there is a mess of down there considering the age of the building and the number units serviced). And along with that, how hard will it be for them to replace this cable? I've contacted the landlord and someone is coming to check it out in a couple days but I'm just worried they either won't replace it or that it won't even fix the issue.

Sorry if this was all over the place, I'll clarify anything needed in the comments, thanks