So it unlikely you will be able to rescue this file.
At first I thought this was similar to this issue: Recover project - Audacity 80.156.6, but now I am thinking that audacity-project-tools needs to be updated from 3.1.3 structures to cover the database changes made in 3.4.0. This would be need to be addressed by @LWinterberg and/or @crsib. Even so, recovery is not guaranteed. It is time for you to find an alternative solution.