[skillachie]

BookFusion sounds like it would be a good alternative for you. You would simple upload your eBooks and use the Send to Kindle option. All the conversions will be done for you automatically. More at https://www.bookfusion.com/reading

https://blog.bookfusion.com/how-to-quickly-easily-transfer-e...

We also have a Calibre plugin https://www.bookfusion.com/reading/calibre