Although sometimes you get lucky and the tech support person actually admits that their routers are absolute garbage and while they won't necessarily say "you should buy your own", they don't fight you and subtly encourage you when you say you plan to do just that.

Frontier tried to give us a dual band, single antenna router. 2.5ghz and 5ghz using the same antenna that just alternates between both networks constantly. The vast majority of my smart devices refused to connect because they need constant 2.4ghz network, not some laggy inconsistent psuedo dual network. Argued with the first tech support person trying to get them to understand that I physically could not use that router until they sent me to someone higher who admitted the routers were useless junk. Oh, and the settings could only be accessed by a web portal with limited functionality. The VAST majority of the features were locked behind customer service and having someone else do it for you. And of course their routers had a built in "free Wi-Fi for all our customers" hotspot set up so you were paying to extend THEIR network as well.

Now I have a "gaming" router with 3 antennas that I have complete control over and all of my devices are happy.