Multiple monitors with different resolution.

I have 1440p 144hz main and 1080p 60hz secondary monitor. Replaced my previous 1080p HMDI monitor with one that only has DP.

RustDesk now only displays 1440p, if i try to lower the resolution, the streamed window gets smaller but in a buggy way where it turns into 1/4 the size but the remaining space isn't filled / doesn't adjust so it is useless and you have to reconnect to fix it.

Is my only option buying a 1080p HDMI spoof dongle?