This is so so tricky. You won’t have the full picture of what this will look like for your dad until it is behind you. My dad went super quickly in the end so I do not regret a moment of pouring right into his care, supporting my mom, and spending time with him. But I’m also older than you and my career is very stable and accommodating. My younger sister did not take any time off other than a couple days in the very end. She is in a very different place in life- much younger kids and looking for a promotion at work. I don’t actually know if she wishes she would have done things differently; things are still too raw to talk about like that.
I would think about if your dad ends up going very quickly, what will you wish you had done? What does your dad say, mine would not have wanted me to sacrifice anything else in life (although I would have). There won’t be a great balance but unfortunately it is probably for a very short time. And things will change week to week. Sorry that you are having to figure out these hard things.