On Windows server, check "Allow connections only from computers running Remote Desktop with Network Level Authentication (more secure)." in Remote desktop settings.
On client, run sudo apt install remmina freerdp-x11 remmina-plugin-rdp.
Start Remmina, create a new connection.
Under "Basic" tab: set "Server" to the IP address of the Windows host, "User name" and "Password" is the Windows account name and password. Leave "Domain" blank, set "Color depth" to "True color (24 bpp)" (or "32 bpp") Set "Resolution" to "Use client resolution".
To enable sound, under "Advanced" tab, set the "Sound" to "Remote". Note this will make the sound from the Windows machine.
Click "Connect" button to connect to the Windows host. After connected, disable "Grab all keyboard events" on toolbar, so you can use Ctrl-Alt-Left/Right to switch between Windows and Linux directly. But if you want use keyboard shortcuts defined in Windows you have to enable this option.
To disable auto-sleep function of the Windows host, in [控制面板 -> 硬件和声音 -> 电源选项 -> 编辑计划设置], set the value of [使计算机进入休眠状态] in scenario [接通电源] to "Never", while keep the value in scenario [用电池] as "30 minutes".
When connect to Windows 10, use the username (here the username is the first 5 characters of my email address) and password of your Microsoft account.