There is another authoring tool, Kotobee. However, I have stuck with Pubcoder, despite winning a lifetime individual subscription to Kotobee in one of their eBook competitions, because:
a) I prefer the Pubcoder interface for ebook creation
b) Pubcoder allows for multiple localisations, which Kotobee does not. My ebooks are multilingual resources; this functionality is central to my published product.
As far as I know, the Android export for Kotobee is still working (or perhaps it's not, and they either haven't realised, or haven't emailed customers about it). Their support is very good though, so I would be surprised. I recently had a 30-minute zoom call with support, even though I'm not a customer! (because I wanted to explore options and new features they've just announced).
They also have a Shelf-type option, which is even less affordable than Pubcoder's offering. I've wanted to use Pubcoder's Shelf for years, but can't afford the expense.
I have also emailed Pubcoder support, adding my voice to the concern expressed by others. I also want to know if Shelf resolves the Android issue, or if it is also affected. I assume not, as they've suggested it as a possible solution themselves. Keen to follow this thread!