Access remote PC through RustDesk without installation

I’m trying to remotely access a PC (attended access) over LAN. Installations on that PC are not allowed.

RustDesk works fine for connections over the internet, but I can’t get local connections to work. I think I got it to work in the past but I’m not 100% sure.

I made sure that the Firewall is off temporarily.

Rustdesk seems to be listening on the correct standard port for rustdesk:

PS C:Usersagospos> netstat -ano | findstr 21118
  TCP    0.0.0.0:21118          0.0.0.0:0              ABH?REN         28084
  TCP    [::]:21118             [::]:0                 ABH?REN         28084

Any ideas what else to try? Or any other software that works without installation?

Note: Installing Rustdesk seems to do the trick (I tried it on a test system), but that is not an option for my scenario.

Note: Using an RDP connection is not possible due to GPO rules, which I don’t have sufficient rights to change.