Seems unlikely to be ‘as good as the app will ever be’. They’ve been steadily releasing updates that add features, and there is no reason to believe that will stop anytime, given the published statements and the schedule, along with the list of ‘bugs’ they’re working on. 

This is perhaps a better question than realised by the OP:

Once Sonos has done fixing all that needs fixing in this mess of their own making, they should say so, loudly, and call a temporary halt on any more upgrades for a month.

Such a discipline will allow users and Sonos elves here to then work on other issues that may be preventing the new app for working as it ought to, including the old chestnut  - it is your network that is the culprit. Just now even if that may be the issue, the waters are so muddied that this is not being seen to be problem at the user end, when it may well be so.

Even if being able to make this announcement extends into 2025 as now looks likely.

But nothing stops Sonos from announcing such an intent even today.

When it became obvious last May how disastrous this new app was I decided to give Sonos until the end of the year to sort it out before I started to seriously consider getting rid of my Port and Five. However, having now decided to get rid of the Five, I am now also thinking about swapping out the Port for a Wiim Pro Plus. I can get a very good deal on a part-exchange right now so really tempted. Trying to convince myself to keep the Port as well as the Wiim but am struggling to come up good reasons to do so.

You can always plug a WiiM mini into the 5 line in its what I did I now have an ultra and don’t use the Sonos App anymore

I’ve been a long time Sonos customer and have amassed an impressive (excessive?) array of speakers throughout my house and they also power my TV viewing. Overall I’d say I'm still in the “Happy with Sonos” side of the pendulum but the way I use my Sonos system, apart from TV viewing (listening!) was almost completely broken by the app upgrade of May.

Music Library stopped entirely due to sudden withdrawal of SMB1 support.

   Having bought a new RAID NAS I got Music Library working again once I read that searching from iPad/iPhone was to return. This does now work buuuuuut many of my albums are compilations and the ONLY way to play them is to navigate the folder system and find them which apart from being a royal pain in the neck not always practical with several thousand albums!
 

Listen(ed) to a lot of podcasts on BBC Sounds and Pocketcasts - the iPad/iPhone integration was great and showed episode play status - this was broken when app upgraded and is still not fixed. Pocket Casts are aware but basically say it is down to Sonos - I know not how much effort they’ve made to get Sonos to fix. I haven’t reached out to BBC but I expect they know and would say it is Sonos.
    I pretty much don’t listen to podcasts anymore using the Sonos API for Pocket Casts and BBC Sounds - rather I use Airplay.

When I consider that I’ve also “lost” about £600 from the 81 shares of Sons I bought when they floated and this ridiculous debacle has helped lose that value I’m unhappy with Sonos right now.

Part of the problem for Sonos is if they polled 500 customers for their use cases of Sonos before the app upgrade then they’d have got at least 300 wildly different scenarios. 

For 10 years I was a vocal advocate for Sonos even buying my sister into the system some years ago and trying to persuade my best friend into it. I would NOT unprompted recommend Sonos now. I would tell people how it is but this insulting mess with the app upgrade has seriously soured my previously high opinion of Sonos. I’d like to think Sonos are concerned by that but I'm not sure.