I don’t use Mullvad myself, but I recently browsed privacyguides.org, which says the following:

Custom server IPs: To counter IP-blocking, you can request custom server IPs from Mullvad’s support team. Once you receive the custom IPs, you can input the text file in the “Server IP override” settings, which will override the chosen server IP addresses with ones that aren’t known to the censor.

Maybe you can ask the support team whether they can give you an IP that is not publicly known as VPN.