Are you using a wrapper dockerfile to deploy Metabase? Is that how Cloudron is running it? (I’m not too familiar with Cloudron)
Our org had a very similar issue with this and one of these additions to our Dockerfile seemed to help:
# Fix /tmp permissions and rebuild font cache (must be root)
RUN mkdir -p /tmp && chmod 1777 /tmp
RUN fc-cache -fv
You’re using a very up-to-date version of Metabase so it should include the necessary font packages already. Might be an issue with your specific config like what the code above helped us with.