Hi
When you connect, from the Remote Desktop Client, you could save a personalized .RDP file to connect to the remote desktop, it will help to keep the settings for that connnection. (You can see the file content with notepad, if you need to validate the resolution)
Check there for reference; https://learn.microsoft.com/en-us/windows-server/remote/remote-desktop-services/clients/rdp-files, the display section.