There were several suggestions in the article you linked to. One was Capture One Pro which looks pretty good. I use Affinity Photo for photo editing but I realize it's not an organizing app like Aperture was.
I have several partitions on my 2010 Mac Pro that I use to boot from to circumvent the fact that Apple has done this to us several times throughout the years. All of my audio editing is stuck on Mavericks with Pro Tools 11 and I have an old Snow Leopard partition to run DVD Studio Pro 4.
Apple loves to make things obsolete. That seems to be their business model. :(