You say "USB" without actually describing the problem you are trying to imply. USB3.x, as I've said over and over again, is a comparatively thin layer over PCIe, and most of that layer is to do with initial negotiation: it completely gets out of the way when it comes to actual data transfer.
Unlike the obscure community hacks needed to make vendor specific SGMII implementations work; have you read the Developers forums on platforms like Qualcomm's IPQ SoCs? Our guys are flying blind and doing the best they can; praise them and Venmo them some money because they're really showing some investigative prowess to make it work at all. Whereas with PCIe/USB3, they've got the entire industry working on their behalf, it's documented in minute detail, and there are entire books published about it aimed at every level of understanding.
So there's NO justification for these endless attempts to deflect new users from a highly performant, reliable, extremely cost-effective and unusually well-supported technology, based on nothing but superstition and some kind of allergy to the word "dongle". USB3 NICs, especially Realtek ones, work spectacularly well on the Pi 4 and benefit from a broad industry support that is extremely rare on the kind of hardware that OpenWRT is typically run on. But every time you try to tell a new user that, someone shows up and offers FUD that they can't document or back up, even with verifiable anedotes, let alone any real data. You still haven't described the "disaster" that's waiting to happen. Because there isn't one. It's as stable, transparent, and low-overhead as any OpenWRT installation and more so than most. PLEASE stop steering new users away from an unusually cost-effective and extremely powerful solution with immense community support.