Which dental restoration gives long term durability and requires no tooth reduction for 80% front tooth?

Strength: If you mean 80% of the tooth remains then a bonding is a conservative option that can give a good prognosis. Ceramic is stronger but depending on how much tooth is left is less conservative. There is no such thing as a proper restoration that involves no tooth reduction but a trained cosmetic dentist can limit the reduction to the minimum. Don't believe the hype about prepless restorations.

No prep veneers: I am not sure exactly what your situation is but the only long term solution for a broken front tooth that is mostly intact with little or no prepping is a no prep veneer (lumineers, or similar lab made prosthetic). You need to consult with your dentist to the best method since all solutions come with benefits and draw backs.

Implant / crown: If you have lost 80% of your front tooth , there is no restoration that will provide what you are asking for. Typically you would need a Root Canal treatment, post/core foundation and a crown. Extraction of the remaining tooth and placement of a dental implant and crown provides the best long-term result. See a Prosthodontist for evaluation and recommendations. Good Luck.