Cactus leather is a new trend. I don't own any cactus leather products so I can't say how good it is, but surely it's possible to replace cowhide with something.
Even vegan (plastic) leather is significantly better from an environmental and emissions perspective than cowhide leather. The tanning process is not exactly eco-friendly, and neither is raising cows.
Just to finish off this Goldilocks story: I've been vegan for four years, and previously ate a meat and dairy heavy diet. I noticed basically no change to my gut health--it has been pretty good, with occasional minor issues, for my whole life.
This is the one for me. Keto, Vegan, Whatever specialty diet I try results in elevated energy and mood for a week or so and then a return to baseline. (Except with keto where I usually have no energy after a few weeks).
Anecdotally, I'm far healthier and more energetic than I was before starting keto a decade ago. I recommend everyone to give it a serious look.
Granted, I can't entirely separate the effects of ketosis in and of itself from an overall cleaner diet with more vegetables and fewer processed foods. It's possible that the same diet with butter swapped out for quinoa would have yielded a similar result.
As far as sweeteners, my go-to is liquid stevia, which I use about 1/5 a cup of daily. When I need a solid sweetener (e.g. for baking), I use inulin fiber sweetened with stevia and monk fruit, which creates a nicer texture than actual sugar IMO. I also have allulose on hand for specific use cases (e.g. caramelizing), but I can't really stomach it in large quantities. I don't particularly like or recommend sugar alcohols for any purpose, but erythritol is the the least bad of the bunch.