Replacing TV battery - AGM or 'regular'?

The TV battery is original - just over 4 years old - and has not been a problem. I'm going to have it load tested and want to get the most appropriate replacement if needed.
I just wired the TV to charge the old trailer battery, a 33ah agm, that will be used to power the Dometic when we have it in the truck. At this point I'm not sure how often it will be coming with us vs. staying in the trailer, but I do like the idea of not having to bring an extra, smaller cooler for those times. So we may wind up using the Dometic in the truck pretty regularly.
As the TV is now wired with an isolator and 50 circuit breaker, would a regular battery be protected from the potential wide swings in demand, or would using the Dometic on a regular basis while camping do a number on the battery's expected life?

 

I had the TV battery load tested, at 3 places as it turns out. First place said it's 'BAD'. Couldn't say why. Next place said it was only holding a 65% charge. 3rd place said it had about 550 cca, which to me is about 75-80%. In any event, I just decided to get it replaced.
I'd seen here and elsewhere the Optima brand mentioned. But saw in a few places that their quality has worsened since they moved their manufacturing facilities elsewhere. Also heard that many of their people moved to or started X2Power battery.
I wound up buying an X2Power AGM battery - #SLI27AGMDP - from BatteriesPlus. No stock, so it will be in next week. Most expensive battery I've ever bought (over $50 in discounts and rebates helped ease the pain), but it seems the best fit for the use it will see going forward.

 

It's done fine - no trouble starting, etc. Not much else that I need from a battery. It was time to replace the original, and this battery should be able to handle the truck's needs.