My 2 cents (and that's probably what it is worth)...
As others have already stated, your situation calls for a trickle charger. They are cheap and might have helped.
A trickle charger/tender is not for recharging a battery. It is for maintenance of a battery that isn't used much. If you want to try to salvage that battery, you need to check the fluid level and
properly correct it (if it is serviceable that way) and put it on a charger; preferably one that can desulfate if it automatically detects the need to do so.
The other thing to do is always check the date of manufacture on batteries, especially those you buy at a box store. If they are more than a month or two old, don't buy it.
Batteries do not last as long as they used to. Partly because of the quality of the battery and partly because of increased demands cars and car owner modifications put on them. Factor in geographical environmental factors like heat, etc and that throws in even more variables.
At any given moment, regardless of the brand name, in reality there are only a handful of automotive battery manufacturers. It can be tough to know who actually made it and how that relates to quality because it seems they are always being bought, sold, merged, etc. Exide, Clarios, East Penn, etc. all make batteries and label them with different brands. If I can find one when I need it, I prefer East Penn made batteries, but that doesn't always happen. I recently had my Tundra OEM battery die on me at the most inopportune time, which is usually the case, and I had to put in a Duralast made by Clarios.
You seem to have gotten 5 years out of your Toyota OEM battery. That is pretty good all things considered. Though a lot of people recommend switching to AGM, in order for it to get the full benefit of the expense of the AGM, you would need to add some things to your electrical system (not difficult) because they have different charging requirements. Only you can determine if that is what you want to do. Personally, if my vehicle wasn't designed for AGM, I'm reluctant to do that unless I need a battery that can take vibration and a beating; such as extreme off-roading and I have a lot of power hungry lighting, etc. Even then, I would go with a EFB battery before AGM if I really needed it and had the option.
COSTCO interstates don't have a great reputation. Personally, I would go to a Toyota dealership and buy a TrueStart OEM if I had the luxury of not being stranded somewhere. They're not perfect, but they're really no worse than any other and might be better in certain respects. I do not know who manufactures them. However, their lower tier TrueStart "True2", which would be an equivalent to the COSTCO interstate battery you listed IMO, is about the same price but has a
5 year warranty. If you wanted to pay more, their higher tier TrueStart EFB battery has a 7 year warranty. EFB (enhanced flooded [lead acid] battery) batteries are between a AGM and regular FLA performance-wise. They are better, more expensive, but don't add the worry of tweaking your charging system. The prices vary by dealership, but my local Toyota dealership shows these OEM 24f TrueStarts at $121.69 and $262.73. I would go get the plain old TrueStart for $122 bucks all day long and put a trickle charger on it when it sits.
True-2 24F #00544-24FT2-530 | Autoparts.toyota.com
Truestart 24F-Efb #00544-24FEF-TS | Autoparts.toyota.com