I'm tethering at home for a laptop and whilst hotspot stays on and internet works fine on the mobile, the laptop gets disconnected at almost the same time intervals. If I reconnect it then it will connect but will say "no internet", only if I turn the hotspot off and back on - on the mobile, it will get the internet back on the laptop until it disconnects again after a while. It's the same for tablets or even had 2 laptops connected at the same time, both got disconnected at exactly the same moment having exactly the same issue.
Limit is off, Power saving off, 2.4Ghz and 5Ghz no difference, Phone mac or randomased also no change... Not carrier issue either as I had Note 8 and it never did it with the same sim, nor my Note 3. This issue however is the same on this Note 20 as it was on another note 20 that I tried, almost exactly the same time interval and exactly the same manner so must be device specific.