Here is a nice protip from one of my readers, Peter, who recently came across an issue with an Intel x550 network adaptor and ESXi not listing any of the Multi-gigabit (2.5GbE or 5GbE) options even though his underlying physical network was setup as 2.5GbE, only 100MBps, 1GbE and 10GbE was available.
After a bit of trial/error, he discovered the solution was to update the inbox version of the Intel ixgben driver (1.7.1.44-1vmw.803.0.0.24022510) to the latest supported version for ESXi 8.x and he immediately saw the additional Multi-gigabit speeds as shown in his screenshot below: