Ubuntu (Gnome) freezes the second monitor, how to fix it?

Question

linux

In general, I use Ubuntu 19.04 Gnome (before that it was 18.04, the problem was there too). GeForce GTX 750 Ti / PCIe / SSE2 graphics, 2 monitors connected, one via vga, the second hdmi (before that it was via dvi, but there was a problem too), proprietary V418 drivers (there was a problem on 390).
The problem is this: Periodically, the second monitor freezes tightly with the picture that was on it, and it weighs like that, while the system continues to function normally, if you click anywhere on the 2nd monitor (the cursor runs over it), the cursor stops clicking everywhere at all (you can only move it), but if you do alt-tab or press the windows button, the cursor hangs and the system works fine, but the second monitor comes to life only after a reboot. I noticed that the hang occurs mainly when you switch between desktops, I think the problem lies somewhere there.