SoftMaker.com

A valid question but yes, speedup of that drive is much faster than a WD NAS, and also if I load the file and export to PDF immediately, there shouldn't be any such delay.
I retested anyway, file size 36KB, 3-column layout with one table on 2 pages. PDF size 470KB, takes 80 seconds.
Another file, no ...

For the records, I had already reported this behaviour back in 2017, but old issues are gone...

It's not paragraph frame if you mean this.
Format - Characters ... - Background color (bottom right) - choose a color - OK
background color is displayed in text on slide
Save slide set, exit Presentations
Reopen slide set - background color is gone

If you set text format to coloured background, after Save/Reopen this attribute is forgotten.
This failed already in Presentations 2021.

Creating a PDF from a 2-page TextMaker file (with a table) takes an instant locally, but doing the same on a network drive (Windows/Samba, mounted via net use) it takes more than a minute.
While this applied to Office 2021 already (and to older versions) for both PDF and HTML, it seems to be fixed ...