Mullvad's mission is to make mass surveillance AND online censorship ineffective. So yes, we do intend to offer excellent censorship circumvention out of the box.
Having said that we have clearly prioritized privacy for a long time. For what it's worth we have several censorship improvements on the roadmap. Stay tuned.
I already see shadowsocks which is nice. I'm still forced to use V2ray and xray-core in some rejoins though so I route traffic from my device -> xray -> my server -> wireguard mullvad. Works for now I suppose. Also been experimenting with routing small amounts of traffic through the syncthing relay network since they have relays running locally which may be in less restrictive provinces
Interesting. Try reaching out to Mullvad's support as well if you haven't done so already. If I'm not mistaken they conduct censorship circumvention experiments from time to time together with customers. I'm sure they'd also be interested to hear about any long-term resilient low-bandwidth channels you've found, such as the syncthing relay network. Those are very useful for bootstrapping and configuration updates.