They do make wet suits with a titanium layer - keeps you warmer. I have one - 1mm rash guard. It would sometimes be too hot in summer.
https://www.scubadiving.com/camaro-revolutionary-titanium-wetsuit
Actually Scuba Diving is pretty safe from sharks.
Its floundering on the surface near seals-prey which will get you in trouble.
I know of thousands of divers who have dove the Red Triangle in CA and who have never even seen a Great White.
I saw one on from the shore following a Grey Whale
Now diving the Farallon Islands off SF...that is a different story.
Probably one of the most dangerous places on the West Coast for White Sharks.