Yes, the Steam Unity version is v5.0, so this version is up to date.
It's a bit confusing with their versioning, but no. The version in the OP is not the last update. We are missing the joypad support from the September 2023 update, and some tiny balance adjustments from the October 2023 update. And yes, they're all still marked as v5.0. The dev just didn't touched the version numbering for some reason. But yes, the Unity version is the absolute definitive version, as the RPG Maker version was cancelled, and thus, never getting finished. The OP does need to separate the RPGM version as the deprecated legacy version, if anyone is interested in messing with that.