Did you find a valid alternative, Dayo?
There is, and has never been, no valid alternative for IView Media Pro 3. That includes Microsoft's Expression Media (Decent despite initial skepticism) and most certainly PhaseOne's Media Pro (Junk despite initial optimism).
IView Media Pro 3 has the strange distinction that almost a decade after it was released, nothing has come close and every iteration released as a successor by new owners has been a downgrade.
A classic example of the well worn Mac Software Road to Perdition of "Great Mac Only Software -> Branches Out To Windows -> Goes To The Dogs"
I tried PhotoSupreme/Idimager but despite the help of resident expert, Mike Buckley, found the logic just too convoluted/complex and just couldn't get my head around it.
In the end, I settled for Neofinder. It is on the basic side but really does everything I need it to do well.
If I were to recommend a DAM today on a Mac, I would say Neofinder is the one.
It is 64 Bit so I believe it would work in Catalina. I am only just about to nudge my relic of a computer to Apple's previous OS version, Mojave, so not tested personally.
Back to CaptureOne, PhaseOne seems to be moving it forward nicely and keeping an eye on the developments in case I am able to get over my animus towards them someday!