With the newest Ungoogled Chromium from AUR
[valeukra@arch ~]$ chromium
/usr/lib/chromium/chromium: symbol lookup error: /usr/lib/chromium/chromium: undefined symbol: wl_proxy_marshal_flags
I’ve included a brief video describing this. Cheers.
moderated - please don’t promote youtube channels
There’s no way you built ungoogled-chromium on the stable branch, it would have failed. Apparently you’re using a 3rd-party repository or downloaded a prebuilt binary package.
Switch to the testing or unstable branch. That error indicates it was built with Wayland 1.2.0 which is not available on the stable branch yet.