Check out https://www.fs.com/c/25g-smb-switches-4247

FS have inexpensive switching and SFPs. Even if you get another brand switch I still recommend FS SFPs which can be ordered for compatibility with various vendor equipment.

Yes the one I linked was 100W / 20V / 5A

For power delivery you need a cable rated for it. Cables can have the same USB specification but different power limits.

Typically to charge a Laptop you want a cable rated for 60W power delivery or higher. I would just go with 100W rated cable as the price is reasonable.

Check out https://www.amazon.com/UGREEN-Cable-100W-Fast-Charge/dp/B07V5MKXJ1/ref=mp_s_a_1_3?crid=3G8AD8YL4Q5XE&keywords=ugreen%2B65w%2Busb%2Bc%2Bcable&qid=1692690249&sprefix=ugreen%2Busb%2Bc%2B65w%2Caps%2C370&sr=8-3&th=1&psc=1

Recordsize sets the maximum it can be for a file.

Either leave it at the zfs default of 128k or since your use case involves primarily reads of large files you could set it to 1MB.

Your network traffic will not go through the new probe IP.

The static route just ensures the probes to that IP use the correct WAN link. Mainly covers the case where there are multiple WAN links and the probe needs to use a specific one.