Are major clouds similar enough for learning purposes?

I have associate/foundations certs in AWS, IBM Cloud, Oracle Cloud, VMWare, etc (I work on a legacy application but learn new stuff for fun:). At that level, terminology differs but principles/capabilities/architecture, and even a lot of details, are fundamentally analogous and broadly similar.

I have opportunity and incentive to dig into Oracle Cloud Infrastructure for free (courses+exams) and possibly get some hands-on experience.

How much of that knowledge and experience might be translatable to other clouds? Is it like learning AIX and moving to Solaris or even RedHat to Ubuntu - yes some re-learning, but very little knowledge actually wasted? Or do the clouds deeply diverge at some level of depth and I'd be wasting my (limited!) energy, time and effort on an obscure weird cloud?