I don't really have infinite money for new/multiple iPads lol, neither has any habitat restoration job I've worked in.

I don't need to keep large documents on hand in my notes binder. I do sometimes print them and file them in an organized filing cabinet though. It's super fast to find whatever I'm looking for, add post-its, notes, whatever I want to them. And I can read them outside without glare.

I have had my phones overheat in sunlight regularly, just listening to podcasts. Not even that hot, like coastal California sunlight. Multiple devices, over years, it's just something I've accepted that can happen when you're working outdoors.

I already described all the advantages of paper notes. They don't break. You don't need to carry extra batteries around. No glare. I would not take an iPad into thick brush on a hot day, I wouldn't even be able to see the damn screen half the time. But you do you!