Even deep fried?
Peanut oil, arachid oil is actually quite stable in deep frying.
Of course no oils are always healthy. And all will decompose when getting to hot, will deteriorate when used multiple times.
The only one that you should really avoid is anything transfat. Even though it’s banned in most cases: I would avoid any vhemically hardened fat.
No oil is truly healthy. Just a bunch of empty calories with maybe some omegas. It’s not really a healthy concern the temperatures; it’s a flavor thing. Some oils taste bad when they reach a certain temp.