Regarding USB4, I need to clarify that the type C ports on this computer are capable of carrying DP1.4 + USB3.2, meaning up to 16.2Gbps of video and 10Gbps of full-duplex data in 2 lane + 2 lane mode (2 DP lanes, each at 8.1Gbps, 1 USB Tx lane and 1 USB Rx lane, each at 10Gbps). This is more than enough for single 4K 60Hz plus 10Gbps of USB data simultaneously.
If you do the math, all four lanes running at full capacity means 36.2Gbps of total bandwidth, which is not bad compared with USB4's 40Gbps. Also, with USB3.2, you get real 10Gbps USB data, while on most USB4 or TBT3 devices, you get USB ports expanded from a single PCIe Gen3 lane, which maxes out at 8Gbps.
While USB4 or TBT3 can carry two 4K 60Hz monitors and this can't, this is probably the only real difference. PCIe passthrough is not really that useful unless you plan to connect eGPUs, and on this machine, the CPU TDP is set so low that gaming was never an option.
That being said, thanks to MST technology, the type C port on this machine can carry dual monitors, as long as the total bandwidth is within the limits. For instance, dual 1080p60 is way within the bandwidth limit, so is dual 1440p60.
In my day-to-day setup, I have a 3840*2560 60Hz monitor connected over DP to my USB3.2 dock, and the dock is connected to a 10Gbps NVMe drive. In addition, the dock connects to 2.5Gbps network. With everything maxed out, the connection remains solid, way better than when I was using USB4 on Intel computers.
TBT3/USB4 is finicky, the connection is very fragile and a little wiggling on the connector may cause a lost of connection. On USB3.2, the connection is considerably more robust thanks to its lower bitrate. In my years of toying with TBT3, I've only found very few cables that remain truly stable over time and mechanical stresses.
Remember I said 40Gbps for TBT3? That 40Gbps is full-duplex, meaning the total bidirectional bandwidth is 80Gbps, so each lane runs at 20Gbps. With USB3.2 + DP1.4, each lane is running at no more than 10Gbps, making the connection much, much more forgiving. Spoilers alert, you almost never have a chance to run full-duplex unless you use your TBT3 connection as an NVMe NAS or multi-10GbE router, which most sane people will not do.
So overall, unless you use eGPU, I don't really think TBT3/USB4 is that important. Yes, it is a theoretical downgrade from my past Intel experience, but I don't really miss the past since I got better reliability and higher data speed thanks to native 10Gbps USB. I used to rely on dual external 4K monitors since I was using a 10" pocket PC and the built-in monitor was really not usable. With a normal-sized laptop, the built-in one is more than usable, so I no longer needed dual external monitors.
