windows server 2012 remote desktop freezes

Since he's the only person reporting issues with the new server (I've been playing around with it, doing some heavy loads and all was fine), and the issue seems to be network-independent I'm thinking this has something to do with his PC or his setup. The only thing I don't know about Bob is that he's using his own PC rather than a company one to connect, and I've no idea how that's set up (don't ask - there's some office politics involved in this bit). Now, Bob has this issue regardless of where he is - he can be at the office using the WiFi, at home and connecting with VPN (we actually have two VPNs, one's using SSTP and the other OpenSSL). It's a newer OS too (Windows Server 2019 Standard vs 2012 Standard), and is actually configured as a proper Windows RDS Server with licensing, as opposed to just a regular Windows Server VM with nothing on it. Now, this new RDS has way more resources than an old one. This lag has been described as a periodic freeze of the RDP image (~10 second freeze every few minutes), which seems like a connectivity issue. A coworker has, indeed, confirmed they saw this lag in action looking over Bob's shoulder. He reports 'lag' that makes working with this server annoying, if not impossible. A certain user (let's call him Bob) has reported issues using Remote Desktop when working with a new RDS Server I've set up.

Windows server 2012 remote desktop freezes