Omnibus GitLab ships PostgreSQL 13 since version 14.1. According to this documentation, PostgreSQL 12 is still the default and HA and Geo are not supported. If this means Gitaly HA (praefect etc.), it is not supported by Heptapod yet.
switch Heptapod Rails CI to PG 13
make PG 13 the default in Omnibus Heptapod
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information