it's happening to the few CN phones i've tried too. Tried on CN HyperOS and CN ColorOS, both having issues downloading/updating apps. ¯\_(ツ)_/¯ maybe google changed something that somehow affected phones without full google services.
already tried clearing cache and data from play store, google services framwork etc, uninstalling play store and reinstalling, restarting phone. haven't tried factory reset or logout/login, but a friend on Redmi K80 Ultra already tried that and still was the same.
additional info: some times seems like randomly if retry every now and then 1 or 2 apps will be able to update somehow. toggling wifi off and switching to mobile data if it's stuck, sometimes will somehow work also.