I feel your passion on the pallet wood. My DH and I built this triple planter with free pallet wood. I absolutely love it and want to build more but DH called a carpentry moratorium until it isn't triple digits outside....I guess I'm into a pallet phase. Years ago I built some pallet compost bins that I still use today. But, back then, it was really hard to find pallets for free. Now, with our new Harbor Freight, they put out lots of free pallets for the taking. So, I am into building more things with all the wood I am reclaiming.
Your pallet garden beds are much bigger than what I am going to build. Anytime you have a long length raised bed, you get bowing out unless you add cross supports when you build the bed. I'll be tearing down the pallets and rebuilding 4X4 pallet garden beds. Small enough not to bow out, big enough to make it worthwhile. If it starts to fall apart in 4-5 years, I'll either just patch it up or rebuild it at that time. I'm OK with not paying $$$ for a cedar garden bed that might last 15 years, or more.
Dear Wife wants me to build pallet planters for the yard so she can have more flowers around the house. We are looking at a number of designs on YouTube. Although I would consider myself a fairly competent carpenter, I prefer the simple designs that are easy to build, looks like a strong design for years of use, and can be easily repaired if needed.
Long term, I'm thinking about a pallet shed build. I have built real sheds and garages before, but, I think it might be fun to attempt to build a free pallet shed just for the experience.

After being loaded with plants -
Breaking apart pallets became incredibly tiresome. Then we figured out it goes MUCH faster when you use a circular saw. Since our slats were all around 15-16" long, this measured out almost perfectly using the circular saw and simply cutting them off the pallet supports