Hello!
Yes, what you write is substantially true, although a server reboot is not needed. The matter has become a FAQ and we added an answer to this FAQ here: https://airvpn.org/faq/wireguard/
In the answer you can see how we patch a specific problem, how you can act through our tools to improve your privacy when you run WireGuard, and all by not breaking original WireGuard compatibility. However OpenVPN under this respect remains widely superior, so consider it according to your threat model and the amount of annoyance you would get to generate new keys after each WireGuard session.
Kind regards