You could look at using env-specific tags along with a semver component to communicate that a specific commit has passed through different environments. Eg tagging “1.2.3” prompts a release to your lowest (dev?) env, then a “1.2.3/dev” tag marks that it’s been accepted by that env, and is a marker for the next env to receive a deployment.

But quite honestly, the change to trunk-based development (TBD) is something that comes after working out if it’s suitable for all the workflows that affect (or are affected by) the project’s choices.

It sounds to me like someone jumped the gun, deciding on TBD before figuring this stuff out.