You already came to the correct conclusion - no solution for this right now I’m afraid, apart from re-running MultiQC with the combined source log files. But it is planned, as part of a major refactoring:
It’s a massive task so it may take some time, so don’t hold your breath. But I’m hoping that we can get to it this year. Feel free to follow the GitHub issue to get updates on our progress.
MegaQC is in use by at least a handful of sites, but it is purely a community project at this point and is not officially supported by Seqera / anyone. It is somewhat functional, but very buggy and incomplete in places.