Reminds me of the terrible delay I faced after having Sophos installed on my Mac.
Having to wait 5-10 seconds for a new terminal tab as Sophos churns (checking autoccomplete scripts, rbenv, etc) was infuriating. Oddly, there was fate sharing with Internet interception, so there was a good chance the browser was getting dragged down too, and vice versa.
Convincing corporate IT of how bad the problem was was maddening. Based on what this author says, 10.15 on rural internet sounds like hell.