For me, the options are Paddle or Lemon Squeezy. Paddle has some of the features I would like, except that they are not really set up for eBooks. Lemon Squeezy looks like it might be better for eBooks (even without StoryOrigin), but they don't yet have some of the features I would like.
Lorri earlier posted a link to Lemon Squeezy's roadmap and some of the features I would like are on the list. So, in 3-6 months, they might possibly have what I want. In the meantime, I can also keep an eye on Paddle.
For anyone that wants to sell direct today or soon-ish, the decision would be tougher. But, for those in the U.S., if you are willing to set up things to collect sales tax in your own state, you probably won't have to worry about collecting sales taxes for other states for quite a while, especially if you're only selling a small number of books. I haven't checked lately so this info may not be current but, last I checked, I think the minimum for collecting sales tax from a particular state was like $10,000 in sales in a year. (Each state varies; I don't remember which states had a $10k minimum and I think there were a couple that had changed from $10k to $25k. It's also possible that a state may have lowered the threshold since I last checked. Regardless, you need to look into that if you plan to sell direct yourself. The point is that, for most authors, you may not have to worry about sales tax issues right away, except for your own state.)
So, you could sell direct yourself using PayPal, Payhip, Shopify or whatever other service you want that still makes you the merchant of record, making you responsible for sales tax collection, and not have to worry about collecting sales taxes (aside from your own state) until you're selling probably thousands of books to a given state. And then, if you're watching your sales, you could conceivably switch before you have to start registering to collect sales taxes.
That's something to keep in mind if you want to start selling direct on a soon-ish basis.
Otherwise, you can wait until Lemon Squeezy or Paddle (or whoever that will serve as the merchant of record so you need not worry about sales taxes at all) comes out with the features you want/need.