I would like very much to read an answer to this question.
I have been relying on Quicksell for years. It has been the cornerstone of my client's online business. After updating to Joomla 4, it stopped working.
If this worthwhile component does not get compatible with Joomla 4, all existing customers will be slowly migrating to other solutions. This is a pity.
Joomla 4 was released on August 2021, that is 1 year and a half ago. Should we keep waiting for the magic update to happen?
If this question does not get an answer, I'll start looking around for an alternative.