Currently, the replica set endpoint tasks use the same tags as their base tasks. The idea was to make those suites automatically run on the same build variants as their base tasks. However, since the base tasks run on both all-feature-flags and non all-feature-flags build variants, we had to manually add "!.feature_flag_guarded" to all non-feature-flags build variants (in SERVER-86406, SERVER-86408, SERVER-88473). It turns out we still missed quite a few build variants (BF-32490) and we need to manually fix add "!.feature_flag_guarded" every time there is a new build variant. Also, we have been talking about making the replica set endpoint tasks only run on the main build variants and possibly at lower cadence due to concerns about costs.
Using a special "replica_set_endpoint" tag would allow us to control which build variants the tasks run on and the cadence more easily.