if it's made for macs specifcally, it's way more expensive; twice, at least. so while it may be usable on non-apple hardware, that's not a good value proposition.
you should look into DIY-ing it. TB4 circuitry from Aliexpress and friends is in the sub-$100 range and all you need then is a semi-decent PSU and the GPU of your choice. they are way cheaper if you can utilise M.2 interfaces, like $50ish.
