PS4 USB Port Transfer Speed
Since PS4 uses USB 3.0 connection and PS4 Pro uses USB 3.1, it’s worth to illustrate the speed of both connections for general knowledge.

USB 3.0
also known as SuperSpeed USB, first appeared in November 2009 by Buffalo Technology. The first certified devices weren’t available until in January 2010. USB 3.0 improved upon the USB 2.0 technology with speed and performance increases, improved power management and increased bandwidth capability. It provides two unidirectional data paths for receiving and sending data at the same time. PS4 USB 3.0 supports transfer rates up to 5.0 gigabits per second (Gbps), or 640 megabytes per second (MBps). Following the release of USB 3.1, it’s officially renamed to “USB 3.1 Gen1” for marketing purposes.

USB 3.1
also known as SuperSpeed+, was made available as of July 31, 2013, and is the latest version of the USB protocol. PS4 USB 3.1 is capable of transfer rates of up to 10 Gbps, putting it in line with the first generation of Apple’s Thunderbolt channel. Today, many devices use the USB 3.0 and 3.1 revisions for improved performance and speed, including PS4 consoles.

The PS4 and PS4 Pro hard drives deliver read and write speeds that hover around 100MB/s at best, while many of the affordable, SATA-based SSDs that can be used inside the consoles offer maximum speeds above 550MB/s

Lol PS4 and PS4 Pro SATA connection is routed to the USB controller because Sony didn't want to pay Realtek 90 cents to buy a storage controller.

What this means is that it doesn't matter if you connect a HDD via USB or SATA, it's still the same speed at the end of the day because everything is handled by the Fujitsu MB86C311B USB3.0 IC.

USB 3.0 (also known as SuperSpeed USB) has a maximum bandwidth rate of 5 gbps (gigabits per second). That translates to 640 MBps (megabytes per second)—ten times faster than USB 2.0 (aka Hi-Speed USB)

5400 RPM drives, 5400 RPM drives offer an average of 100 MB/s read and writes speeds

It doesn't matter like I said.

ALL storage is handled by the USB 3.0 IC on the PS4 pro motherboard. The bandwidth is capped at 5Gbps (which is more than enough for HDDs, but not enough for SSDs), doesn't matter if you use the SATA 3 connection or the USB 3.0 port.

Also, you are misunderstood that the PS4 Pro has USB 3.1 10Gbps speed. PS4 Pro only has USB 3.1 Gen 1 speed, which is the renamed spec of USB 3.0.

https://www.playstation.com/en-my/ps4/tech-specs/

Input/ Output
Super-Speed USB (USB 3.1 Gen.1) port × 3

https://www.ps4storage.com/ps4-usb-ports/

USB 3.0/3.1 Generation 1.
Both, the standard PS4 and the PS4 Pro are packed with USB 3.0/3.1 ports.
The PS4 USB 3.0 has a SuperSpeed transfer rate of 5 Gbit/s which can transfer about 625mb/s.

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PS4 Pro supports SATA III

With SATA III support, the PlayStation 4 Pro's hard drive storage can hit read and write speeds of up to 6Gb/s, or 600MB per second. (in theory & this matches the USB 3.0 transfer rate, so.....the system architect decided to...)

The PS4/Pro internal SATA bridge is connected through the USB chipset.
https://www.psdevwiki.com/ps4/MB86C311B