Fuck pitchford and all that. But this is an increasing problem that most games have. Shaders are getting more and more expensive and compiling them on the fly.. when it works it works and when it doesn't it is horrible. But having a mandatory "sit and watch this load screen for three minutes" starts you off with a HORRIBLE first impression during the period where it is easiest to get a refund.
It is why MS are setting up their convoluted, and destined to fail, system to add those to the downloads. Since people have increasingly been realizing that Proton/Linux weirdly have an advantage in this... that again mostly manifests during the first 30-40 minutes of benchmarking while writing a blog post.
In this case? Not sure if they were doing some shenanigans to lessen the cost of on the fly compiling. But odds are that some performance tweaks they put in a patch invalidated those and... yeah.