You can self-host Uptrace and use it in production environment. This is explicitly stated in the FAQ - https://github.com/uptrace/uptrace#faq . But you can't resell Uptrace to others.

I can only repeat that the same BSL license is used by MariaDB, Sentry, CockroachDB, Couchbase, and others. I am not a lawyer and thus not qualified to discuss details.