Alulose, monk fruit, stevia. There are 3 fully "natural" sugar alternatives.

I agree that sugar alcohols can be bad for your gut and liver. As well as some are cut with carcinogenic fillers, but there are sugar alternatives that have VERY little effect on you. And actually alulose can be beneficial to your gut microbiome, while not affecting calorie intake and liver processing

Stevia, if the aftertaste doesn't bother you, is definitely the most affordable and passes through the body with barely a trace. I know you didn't mention cost, but I do admit that alulose is significantly more expensive than sucrose. Around $30 for a 5 lb bag vs $8 for a 25lb bag of sucrose. But Stevia is often sold without filler, like xylytol, which a lot of monk fruit is unfortunately cut with to make the amount bigger.