There is also paddle, which has been around for a lot longer: https://developer.paddle.com/classic/api-reference/4c7d88de5...
I looked at paddle initially, but was not too happy with their chat support. The content of the support was great but the response time was about 1 day, which made it difficult for a chat type conversation. In retrospect, I could've tried writing longer messages.
So I was looking for an alternative and found LemonSqueezy. One of the founders actually helped me onboard, which I was very grateful for. At the beginning the support was great, but it has degraded a lot since. If you go to their slack, you would notice many people complaining about issues being unattended to for weeks and months. I've had first hand experience with this too. I suggest you go to their slack and check out the state for yourself.
In contrast, paddle's response time was better and higher quality too. I'm strongly considering switching to paddle at this point.