That makes sense from both the Google and Huawei perspective that existing phones would continue to get security updates. Just as Microsoft provides security updates to people running non-genuine Windows 10. The companies don't want the OS ecosystems to become infested with malware. So if the situation between the US and China were to crash again all you might risk is no more OS updates.
Microsoft is updating non-genuine W10's, as it is the easiest way to implant updated spyware on these machines. They learnt a lot from
Google on that matter...
Apple is using updates as a technique to push sales of new phones. It was in my case of iPhone 4 which was rendered partially functional after update to iOS7, but there are other cases too.
I do update my phone only when I see bug fixes that affect me or real improvements indicated in the log.
Google FoolPlay Services prompt me
every day to update my Huawei phone. If I do, ACR may stop working (which is widely reported on the Internet). When I do refuse, I am being asked again to accept new Google agreements (which should not apply to the current version of software, but they do ask anyway). And finally -
the third time in a row - I am being asked whether to update over WiFi, in a continuous hope I would press a wrong button. A real hostile environment.
From the competition point of view, it would benefit users if Huawei had released their own OS free of
Google FoolPlay Services, giving users a choice.
Companies have more strategic goals than protecting someone from poor malware. Huawei refused at a time to install CIA/MOSAD backdoors on their 5G routers, it is why they are on the radar. What is a reason to lift a ban I don't know, maybe because they realised that Huawei is one year ahead of US-based companies in 5G technology and world cellphone companies were already heading towards Huawei solutions despite of sanctions in US. The war is about controlling the entire 5G network, not just cellphones.
As for the phones, Huawei currently makes the best handsets. Not just flagships (unlike Samsung in the last few years), but also ordinary low-cost Y series. A default strict power management can be annoying, but there are configuration options to deal with. The EMUI interface is the most thought and polished, there are couple monitoring utilities helping users with common problems and cameras are - undisputedly - the best quality, even in the entry-level phones.
From the music lovers point of view, Huawei do not offer outstanding quality over 3.5mm plug, but they seem have heavily invested in HWA/LHDC initiative, the first royalty free codec for Bluetooth (LDAC, aptX are not). All 2019 Huawei phones with Oreo or above support LHDC, I don't have a compatible headset to test and I have yet to see user opinion.