One deep discharge won't destroy the batteries. It may have shortend the lifespan but probably not fatally.
Here is the other bad news. Battery
chemistry was pretty much old news 40 years ago. There really are no new magic batteries on the market. There is however a lot more ways to make you think there is. The price
of lead has gone nuts in the past few years and battery
prices are through the roof - for all of types. I would be a little bit skeptical of anything that claims to be "new" or somehow significantly different. If you price
them out you will find they are about the same as any other premium battery. It's not to say anything negative about them but there is nothing new about batteries.