The new desktop outlook app and the outlook on the web does not seems to care about addressList container.
Unless there is another way to achieve that, it would be very have the container shows it's child rather than having all the addressList ungrouped. I don't know how big organizations handle that.
If there is something obvious I'm missing please let me know, but from my tests, the lists are not grouped by container in the new version of outlook
The only place I could see this discussed is here Oct 2022
https://techcommunity.microsoft.com/t5/exchange/make-a-container-for-addresslists/m-p/3660314 where it says that OWA doesn't support this. According to my test pc desktop version of the new outlook doesn't support it either.