I am making available the previous CE of osCommerce called Frozen. With Bootstrap 5. It's about 60-70% completed, I can work on it as my time allows.
https://www.dropbox.com/s/i6pdg383k67otql/defrosted-master.zip?dl=0
This is a feasible option for anyone wanting to start with osCommerce. Also the majority of addons will still work with it.