Just tried this but got "this device needs iOS 15 or later" when trying to install Microsoft rdp client, which isn't available for my old iPad. So I guess you can't actually use an old iPad for this. But maybe I can find another rdp client that will work.
Do you have the RD Client app installed on an iOS 15+ device? If you ‘own’ the app (and the developer allows it, I think) the App Store will let you install the latest supported version on an older iOS. I was able to install RD Client on my iOS 10 iPad that way a little while ago, but maybe something’s changed in the meantime.
It doesn’t work on X11, and the cursor is not showing. But if don’t need it, works pretty well.
does this work in KDE too or is there a similar solution?