OpenVPN and WireGuard are two protocol choices you have when using most commercial VPNs. WireGuard is faster but there are some trade-offs you should understand. This article goes over the basics between them and which protocol is better for your situation: https://simplifiedprivacy.com/vpn-protocols-which-one-should-you-use/
On the website :
However proton Vpn în their app, they have a “wireguard TCP” setting.
Which is also confusing as on their wireguard marketing page, there is a faq where they say openvpn supports tcp in a ways as it supports TCP but not wireguard.
Proton uses their own Stealth Protocol, which puts a TCP/TLS wrapper around the Wireguard protocol.
WireGuard supports UDP/TCP
This is my issue with Wireguard. It is not good a firewall traversal. On restrictive nets really you have to get out via TLS port 443. No other way often works. So for the traveler OpenVPN TCP option can be way better. Nice to see Proton has a solution.
The other problem with Wireguard is that it is not necessarily as anonymous. The good VPN providers had to do special things to make that so.
Other then that, Wireguard is wonderful in terms of performance and presumably security too.