This app was mentioned in 1 comment, with an average of 1.00 upvote
Ok, I've just played for a while with ARC Welder converting a few RDP clients.
The only one I could get to work is Thinstuff's RDP Remote Desktop Connection
It works great so far, only issue is that ctrl+ and alt+ key combos aren't getting thru. The Microsoft's one loads but fails to connect.
I'll try a few more but right now this one looks good and is fast on my lowly 1st gen arm chromebook.