Here is a travel VPN router that is compact enough to fit in your pocket and runs open source software. The Slate GL-AR750s is a dual bad Gigabit router with speeds up to 300Mbps(2.4G)+433Mbps(5G). It also has OpenVPN and WireGuard installed and supports over 25 VPN service providers.
The device comes with a microSD card slot, 3 Ethernet ports, and a USB port. It can use the TLS for encrypting DNS queries.