Unless you're at a theme chop shop, then you might as well move onto greener pastures. There are so many alternatives now for website control panels like Wagtail, Payload, and Craft CMS.
No, mostly ground-up custom built themes. I've tried Craft and found it pretty convoluted (althought that might just be familiarity), but will be looking at Wagtail. Still hoping that WP can pull out of the tailspin because it's going to be a huge headache to switch.