Then again Odin also states as long as Asgard exists, Hela will continue to grow more powerful, is functionally immortal, and will keep drawing strength it. The Asgardians are also aware of the Infinity Stones and had a replica of the Infinity Gauntlet in the Vaults of Asgard and weren't too impressed by it either. Hela was drawn to the power of the Eternal Flame over the Tesseract. I don't think Thanos without most of the Infinity Stones even stands much of a chance against her given what Tony in the Mark 49 or 50 (can't remember exact model of his Iron-Man suit in Infinity War) was putting up a fight against him and managed to injure him even when Thanos had the Power, Space, and Reality Stones.