I mean, yes and no. If you upgrade to Android 14 you get to keep your apps. But you won't be able to install any apps targeting Android 5.1 or older, they claim because malware often targets older API levels that have more access. I tend to believe that, Android 5.1 was released at the start of 2015 and a lot has changed since then. And people get texts with downloads of apks, and actually install them.
But I still believe you should be able to disable that protection if you want to (and do we know you can't, in developer settings?).
For me, the question is whether I have the right to use a device I bought as I want or not. There is, rightly, a lot of talk about "right to repair," but now the issue is becoming "right to use".
Can I install an old application that I still find useful or should be the operating system to decide if i can use it, without there being an incompatibility issue?
Can I decide what permissions I want to give an application or should the Play store (and protect) decide without appeal what I can do?
I would argue that because this is a new OS and not an update to an existing one, "right to use" doesn't really apply. Just don't install the new OS.
OSs make decisions about what we can run all the time, intentionally or not. But as long as you aren't prevented from using what you already have, I don't really see it as a "right to use" issue.