As others pointed out, it's hard to say how much copyrighted material the model already contains in the weights. The bigger problem is the legal system isn't a logical system, it's a social construct. The reason why it allows cleanrooming is its how it promotes understanding, creates labor, and is generally too expensive for your entire product to be wholesale copied the moment you publish it. There's an underlying social contract the legal contract only exists to mirror.

It's my personal opinion Synaptics should go bankrupt along with its cancerous mountain of patents, and the copyright system itself reformed to finally end its reign of terror of over both art and engineering, this requires coming up with a better social contract than "I got mine fuck you", or the entire world will turn into Temu crap.