Apparently creating blobs in ./playwright-report and then merging them into the same directory (./playwright-report) will generate corrupt trace files.
Solution was to use one directory for blob generation (./blob-report), and a separate directory for merging reports (./playwright-report), after which trace files will be usable
Also turned on trace files for all failed tests (originally only for 1st retry).
on-first-retry option only records for 1st retry
retain-on-failure records for every test, and then deletes for successful tests. This is apparently not recommended because it will take significantly longer than on-first-retry. If it takes too long, we can disable later
Apparently creating blobs in ./playwright-report and then merging them into the same directory (./playwright-report) will generate corrupt trace files.
Solution was to use one directory for blob generation (./blob-report), and a separate directory for merging reports (./playwright-report), after which trace files will be usable
Also turned on trace files for all failed tests (originally only for 1st retry).