Why can RDP connection establishment be slow?

Question

Windows

Hello everyone, tell me what could be the problem, there is a small local network through a Zyxel router, for a long time and in the local network everything has always been 100% normal with all computers, and now it’s normal with all but one, i.e. it's not about the network, there have never been any problems with the router, so on one of the computers there was a freshly installed Win10 1909, at first everything was fine with RDP on it - a quick connection, then suddenly problems started in Windows without any changes - either it connects for a long time, until the appearance rdp window for entering a login and password, or this window appears quickly, but then it takes a very long time to establish a connection - setting up a remote session, protecting a remote connection, etc. - all these stages take a long time, the network is not overloaded with anything, this computer too, everything is as usual, and sometimes it connects normally as usual - quickly i.e. after connecting, RDP works fine, without brakes, as usual, quite quickly, but if you leave the window open and do not touch it, or even if you turn it off, then after a while it turns out that RDP is frozen, and the remote computer itself does not freeze - if you close the window and connect to the computer again, then everything continues to work on it as it was, before this has never happened with any versions of Windows either in this LAN or on this computer, for the first time I see this, tell me how can I fix it?