If Aperture is that valuable, have you considered just keeping an old Mac around dedicated to Aperture?
(You don’t even have to go that far yet, since you can still get Aperture working in Catalina, and Mojave and High Sierra are still viable options. But, for the future.)
I certainly could still run it, but it’s just not worth it to me anymore. Over time I gradually stopped caring because it wasn’t a rewarding way to spend my time anymore. This thread just jogged some really old memories.
(You don’t even have to go that far yet, since you can still get Aperture working in Catalina, and Mojave and High Sierra are still viable options. But, for the future.)