It was a very long traceback. Unfortunately I didn’t copy the whole thing.
I managed to upgrade by applying the changes in https://github.com/getsentry/sentry/pull/6132
The commit https://github.com/getsentry/sentry/pull/6132/commits/9f7f3fe649c7fcd03df7d3d31fe6268826966e4b simply ensures to run yarn before running webpack and that solves the issue about the missing camelcase.
The other two commits are related to the fact my server (being located in Cuba) can’t synchronize the documentation.