Hela vs Thanos with stips
3 fights. Thanos knows what Hela can do and her capabilities.
First fight is H2H
Neutral ground and Hela can only heal the first 5 hits.
After than no HF.
Second fight
Thanos gets his bladed weapon and Hela gets only 1 bladed weapon. If she loses it or it breaks then she can make another.
Hela cant heal from severed limbs.
Third fight
Neutral ground
Thanos gets bladed weapon and power stone
Hela can use all her powers. Shes not in Asgard so you can debate the limit of her HF (whether she has one).