Considering the demands aren't going to change, what skill(s) could I develop?
I have been working in unfamiliar territory for so long that it's become one of my strengths. The first skill to develop in this domain is that of acceptance. Accept the unfamiliarity. Accept that you are going to do the work. Accept that the process is going to painful at times, and realize it isn't going to be painful all the way. After you accept, consider how much further you may go if you actually embrace your work. You're going to have to do it, so why not give your best? This may likely require you to put more into the process but the accomplishment is how you reward yourself.
You can become a generalist with specializations. You don't have to only be one or the either.
Range: Why Generalists Triumph in a Specialized World
The author went on lots of Podcast shows, you can start from there before you spend any $.
MeganWachs - Keynote RISC-V and FPGAs: Open Source Hardware Hacking
https://www.youtube.com/watch?v=vCG5_nxm2G4
And just keep diving. Get low level. I think next gen cloud architectures, gpu, tpu. Next gen lidar, radar. Playing with 4D point clouds in VR. That's about as hot as it gets right now ;)
DigiKey & AdaFruit "All the IoT"
https://www.digikey.com/en/resources/iot-resource-center/vid...
As far as specialties inside DevOps - security, OCI, schedulers are general areas that have specialist roles available. Another option is to specialize in a tool or tooling ecosystem relevant to DevOps. For example, you could decide to learn AWS service offerings inside and out or specialize in webtech on bare metal and land a role at a company that has the scale to demand optimal bare metal deployments.
I'm in biotech, and being the "software guy" on my team has left me in a similar situation, and I asked the same questions for how to market myself to Ph.D. programs, which are all about specialization.
Or, if you have time, contribute to some Open Source tool you use or like. It can help with differentiating.
In doing the many random things, have you noticed any that you enjoy far more than others? If so, then it might give you an ideas as to what area to focus your learning and development upon.
Not to deep, just understand the difference between opex, capex, and what implies to your job.
This will make you able to speak with the business inthwir own term.