Is there any way to put an accent over a slash region like this at certain spots? I’d like to accent each chord change, but not be so specific as to add an extra slash voice and its value.

Is there any way to put an accent over a slash region like this at certain spots? I’d like to accent each chord change, but not be so specific as to add an extra slash voice and its value.

I can’t find anything in the manual, so I don’t think it’s possible to put an accent in a slash region. However, if you set up one bar with a stemless slash voice with accent on the first beat, and fill the rest of the bar with a slash region, you can copy/paste that bar wherever you need it.
To get the accent to appear over the staff, you’ll need to change this option in Engraving>Articulations>Vertical position>Advanced options.
Yes, of course. That’s maybe not the ideal (IMO), but it certainly does the job!