Preview not saving annotations

Preview is not saving my annotations of PDFs that students submit. It saves one or two and then stops. Apparently security settings create the problem but it's not feasible to tell the students to make sure that they disable security -- too many of them will forget. That's a problem. The technology should reduce barriers not add them. There was not problem with the annotations until I got my new mac at the end of 2021. Before that annotations worked without having to tell students to adjust security settings. I can see that if I open the files in Adobe I can save the annotations so it's an Apple Preview problem not a PDF problem. Unless there's some sort of fix for this (searching the discussions suggests that Apple does not see changing this as a priority) I will have to look at this as Apple broke Preview and I need to use Adobe to edit student papers. If there's a better solution I'd love to hear it.