Ubiquity's issues are extremely frustrating. I *suspect* the reason they fail with a Fing box is on their end. But, like you say, they've known of the issue for at least a year (given when I told them) and nothing.
As far as I can tell, they do not do ”bugs”.

If something works great, if not and it gets fixed in some future release, great. Otherwise, it is what it is.
OTOH is there anything else that's overall better? I keep hoping Alien at least gets it right, and that those issues will go away when they release a 6E Alien.
No, there is nothing better. Lots of things that are different, but not better. I have a UniFi Dream Machine Pro, a few of their 10Gb/s switches and lots of their access points. Before I was able to run fiber to the house next door where my b/f’s office is, I used to mesh the networks using their WiFi. My experience was it was not that reliable. Once I switched to fiber connecting the switches and all the APs directly connected to the Ethernet, things got much better and more reliable.
A second problem is that Apple itself seem horribly incompetent. In particular if I use my aTV HD as HomeKit hub, automation is mostly reliable. Not what I would consider acceptable, but failing say 1% of the time.
I am curious what kind of automations you have. I presume more than time based, but how complex are they?
When they fail, what happens? My single biggest issue with HomeKit is there is not reasonable logging/debugging. I have considered adding a HomeAssistant item to every automation, so at least I could know if they were firing while I was debugging. (I would love an easy way to add automations in Python or Swift, but that is a bigger ask.)
But when the HomePod (older, big, model) is the hub automations fail about 1/3 of the time. I don't believe this is radio related -- the two are in the same room. It feels like HomePod is just using a different (and substantially more buggy) codebase for HomeKit.
Last April, HomePods were switched to tvOS, I would expect they are running exactly the same code. It would not surprise me if the issue were networking based (differences in the WiFi). I know that we have our AppleTVs connected to Ethernet because we found it more reliable. I have had occasional connectivity issues with the HomePods. I wish they had made them PoE powered, so that they could have had Ethernet and just used a PoE injector for people that did not want to plug them in to powered switches. 🙃
Of course Apple, in their infinite wisdom, don't allow one to choose the hub, and since iOS14, HomePod has been the winner. Which means that HomePod has been powered down for quite a few weeks now -- the house just does not function properly if it has control... Every iOS update he gets a day or two to prove that he's competent, and so far he has failed every such test.
Yup, I can see that annoyance. In one Home I have 9 Home Hub capable devices (2 HD AppleTVs, 1 4K AppleTV, 6 HomePods including 2 in a Stereo Pair). It always seems to default to the AppleTV HD in the Master Bedroom.
I consider things like "having to maintain a separate network [or separate SSID] for IoT" to be unacceptable. Like I said, I have zero tolerance now for this crap.
As I said, I do it for several reasons, most of which I would do even if all the gear was 802.11ax and worked on 2.4GHz, 5.8GHz, and the new 6GHz spec. However, I do agree that this stuff should just work, without needing to do it.
It was cute and interesting when I was in my 20s.
It even annoyed me then, that was why I used NeXTSTEP, macOS X and FreeBSD, to avoid those kind of problems.
Now that I'm retired, if you don't work -- ALL THE TIME, under ALL CONDITIONS, I rate you as garbage. pure and simple.
That is where we differ. I want my gear to work reliably once it is configured, but I am willing to endure a small amount of pain getting it configured. Mostly because I know my configurations are going to be very different than almost everything they will have tested. (I remember a problem I had with TiVo that took a long time to debug based on a hard limit on the number of boxes on one account that no one even remembered existed as it was the first time it had been encountered in the real world).
Things that have setup issues definitely are rated lower than those without, but I only rate things as garbage that do not work once they are configured.
I have the NetAtmo Indoor Home Air Quality monitor. I bought it specifically for the CO2 measurement (since Eve does fine with general VOCs measurement). And of course the CO2 measurement is completely borked -- it mostly measures zero, then something random happens and it squeals that CO2 levels are dangerously high. That's apart from the fact that, once again, it can't maintain a HomeKit connection longer than a month without having to be rebooted.
I presume you have talked to them about the problems. What was their response? I have found their support people better than average, but that is not a high bar.