Finding appropriate shorts for my Arione

I’ve recently been bought a Fizik Arione R3. I’m aware performance saddles are tougher than stock saddles for entry-level bikes, but I’ve found myself somewhere between real discomfort and in outright pain.

Shorter rides are good, so I feel like the fit is appropriate: though I’m relatively inexperienced so I have little authority to say.

I think the issue is that my bibs are cheap (never more than £25), and by the 90 minute mark of any ride – it begins to hurt quite a lot. I’m slightly reticent to blame the bibs because surely even cheap shorts would make my saddle feel a little less like concrete?

I really am a little lost, and if anyone could offer some advice that’d be greatly appreciated. (I’m happy to fork out for some higher-end bibs if that is the problem)

Thanks in advance!