What works well from your end? Shall I share a backup of the web page in joomla 3 and try it on your server?
With the pages that I am migrating to Joomla 4, the same thing is happening to me, so it is not a one-time thing.
I add data: When uninstalling SP Page Builder to upgrade, ALL MODULES created with it DISAPPEAR. I find it incredible that these errors appear when joomla 4 has been running for almost a year, we have been in betas, alphas, gammas and omicron for almost 3 years and NOBODY has had this problem.