Zen3+ does not have a USB40/TB4 SoC inside.
AMD's first chips with native support for USB40/TB4 (despite the lies of their marketers a year ago) are Zen4, and not all of them, but only the Phoenix 7x40 series with a "4nm" technical process. There are officially 2 built-in USB40/TB4 ports.
The Zen3+ SoC is connected to USB40 via a Parade 8830 interface chip. Just like the H version of Alder Lake, which also does not have built-in USB40 / TB4 ports.
Only U/P series have built-in TB4 ports. And that's why the i7 1260p is faster with an eGPU than the i9 12900HX. That has already been proven by tests.
The most disappointing thing for those who buy now is that TB4 will become morally obsolete in a year. Runs TB5 with pci-e 4.0 x4 (or pci-e 3.0 x8) and 120Gbps for DP ports. 2x60 and possibly 120Gb/s per monitor, but it's not clear because DP2.1 does not support more than 80Gbps according to the standard (UHBR20 lane mode).
Therefore, if there is something to sit on for another 1-1.5 years, it's better not to twitch and wait for TB5 and full-fledged DP2.0 (2.1) ports with 80Gb / s and full-fledged HDMI 2.1 in every laptop. This means that 8k monitors and real 4k @ 144-165Hz are flourishing on the market, i.e. the junk that is now sold on the market in lossless mode 4: 4: 4 144-165Hz with HDR on the "HDMI 2.1" port is not supported for a banal reason - this port is cut off to 24Gb / s in them and in the built-in / discreet.
So a radical change in video standards and eGPUs will begin in 2024 towards the end of it...