So,
rolling back to 42.7.7 has no impact on the performance drop.
Given the changes on GitHub (https://github.com/xwiki/xwiki-docker/commit/389255b066150c314db18921de98742b1ccc496d), I reverted to version 42.7.4.
With this version, we have returned to normal performance.
So I tried with versions 49.7.5 and 49.7.6 and it works fine.
Logically, the problem appears to occur starting with version 49.7.7 (https://jdbc.postgresql.org/changelogs/2025-06-11-42/).
