You should be able to do it. Unless Photos in Catalina has changed anything, stacks are "unstacked," and if I remember reading it right, ratings are converted into keywords. (Either that, or it was a recommendation that I had read to manually indicate ratings with keywords in order to maintain some sort of rating system in Photos.)
For what it's worth, if you have Parallels and VMWare Fusion you could install a macOS 10.14 virtual machine and continue to use Aperture from within there... but having personally switched from Aperture to Capture One about a year ago (maybe two, at this point), I'd suggest doing yourself the favor of changing to a more modern program. It's painful to do, but it's worth it.
Also for what it's worth, I changed from Aperture to Photos before going to Capture One. Photos still lacks a lot of critical features, such as comparing two photos large side-by-side, or having a meaningful rating system besides "love." If you used Aperture as a glorified photo organization tool and little else then Photos will probably work fine for you. That's pretty much how I use it. But for photo ingestion and culling, as well as heavier adjustments, it doesn't cut it.