We can probably never get rid of animal testing entirely for clinical research, we’ll always need to validate simulations in animals before moving on to humans.

Getting rid of animal testing is the exact purpose of organ-on-a-chip research! This is actual bioengineered cultures, not simulations (not dissing on computational biochemistry - also extremely important)

If you can test without the full animal, then models (in this context, models = what you use for testing, be it cultures or animals) based on human induced pluropotent stem cells (ie cells taken from live, adult humans and forced to revert to a stem cell status) in an in vitro setting can actually be more relevant to human physiology than live animal models.

There are a lot of caveats (if it were easy, it would already be done), and there are barriers needed to be overcome for in vitro models to even come close to in vivo and ex vivo models. But a lot of people are investing in it, not (only) due to ethics but also due to lower model cost and better match of in vitro results with the actual effect on a live human body.

I can give papers when I get home, if you want.

Edit: I went on a deep dive on medical applications: suffice it to say, this is useless for behavioral experiments