The time I've been stuck in these situations, it's mostly about inflicting or bringing notice to enough pain that the business backs off on some tighter deadlines to give more time to automate the tasks that will free up the most bandwidth or time - and it's a lot of small bites. I typically will start (if I can) by insisting anything new that makes sense to be automated (making a basic estimate of time per week, and effort to automate, also something you need to factor in is long term maintenance to use as a pitch to sell to management) and stick rigidly to that until it starts taking over other legacy processes in sort of a slow strangler pattern. This can look wildly different depending on the infrastructure setup and needs and how much firefighting you're doing - which there is usually a lot of. So sometimes that first step is just putting out all the fires or gaining enough visibility/monitoring to ensure you know what fires need to immediately be jumped on and which ones don't, and most importantly, proving that to the business.
Unfortunately though, leadership buy in (to me) is the hardest part almost always which is why I say "inflicting pain" the way I do, it sounds bad, but if they do not feel pain you will never, ever get priority to do anything, because IME like I said "devops" guys to most businesses (and even a lot of technical people) are glorified sysadmins that cost and demand way too much.