Google DNS Unstable For My ISP And I Think Something Is Going On

For some time I have been using Goolge’s DNS servers, i.e. 8.8.8.8 and 8.8.4.4 and they are working fine. The reason behind this is the DNS advertisements going on in China, and the other reason is, I really don’t feel that good, knowing my ISP actively pushing its own DNS to all my devices connected to its network. When I say actively I really mean it, like every 5-10 minutes. On PC it’s really simple just set a specific DNS and that’s all, the same is for my router. But on Android devices, DNS can be set for WIFI but not for 4G or any mobile connections, unless you have root access.
I don’t know know the exact reason behind pushing so hard for those DNS servers, but as a rule of thumb I really don’t trust any of them. Let’s say the worst case could be, by pushing those DNS servers to all my devices, almost all my internet connections would have to go through those ISP DNS servers first. Those ISPs have all my personal information and can link my IP address to me personally without any problems. If they keep a record of all my DNS requests, they would have a almost complete metadata of my daily internet usage.
If metadata collection in those so called democracy countries is scary, and within China is downright dangerous for people like me.
But from what I can see, Google DNS is no longer a stable option for my concern. For several times a day maybe more, all 2 Google DNS services would be down for 5 minutes more or less. It’s not my internet is down, no. Pinging those 2 DNS servers shows the servers are still up and running. It’s just the DNS packets are somehow not making it.

This makes me nervous. I have seen how the GFW over the years blocking Google’s search results while Google search was still not completely blocked. The GFW would disconnect users’ connection to Google once in a while, creating a user experience that Google search was not stable, not usable, so that users of Google would have to turn to other domestic search engines. After a while when almost nobody was still using Google, the GFW blocked it completely and almost nobody noticed. When news came out saying Google was “blocked” the state media would say its services were never stable and other BS, internet users would agree because they knew no better. This tactics was so successful that I am afraid they are using it again, but this time aiming at DNS services.
What they want is in fact data. Over the past several years I think Chinese gov has been trying to gather as much data as possible and trying really hard to figure out a way to use all these data. I don’t believe they have made much progress in how to use the data but having them and keeping them are certainly disturbing enough.
Anyways, I would have to figure out a way to deal with it. Like many times before.