You need to push to get 1-2 junior devops engineers that you can handle the day-to-day tasks (unblocking engineers, fixing common issues), so that you can focus on larger picture tasks (evaluating new technologies, setting strategies, etc.). The story you need to sell is that investment in devops will make all the other engineers faster (better CI/CD, less manual work, etc). And that only having a single devops engineer limits the amount of unblocking that you can do (which will slow down engineers) and leave no coverage when you go on vacation (and you should be going on vacations).

The goal is to identify common problems and have junior engineers fixing them and working with you on how to automate your way out of that problem. And you are setting the devops future plan. What are the tasks/technologies you need to do and how will it speed up the developers? And that's what you need to sell, speeding up developers and making their development life easier.