Very strange that that model does not show up in a search on the ASUS website NOR is it listed as an existing model on PCPP, at least, it wasn't both times I looked for it. Clearly, it exists though so right on for linking to it. Google was not bringing up anything for me either. Sometimes this happens if the model is non-US region limited, but this doesn't seem to be the case in this case.
To start with the PG lightning has a better VRM power phase configuration, with a 41+2+1 power phase while the B650-Plus has only a 12+2 power phase, which might not matter depending on what CPU you plan to run in it and whether you intend to run PBO or manually overclock, or neither.
Both have 2.5GB LAN so no real winner there.
Both have 3x NVME M.2 slots.
The lightning board supports USB 3.2 Gen 2 for case front panel connections, which the TUF board does not. It only has 3.2 Gen 2 on the rear panel. Both have 3.2 Gen2x2 on the rear panel as well. In total the ASUS board supports 15 USB ports of various types while the ASRock board supports up to 19 ports. If you use a lot of USB ports, then the advantage is ASRock here.
ASUS does not specify what audio codec is onboard with this model, only that it is Realtek 7.1 custom codec, which I have little choice but to assume means they've gone with a less than premium codec here while the ASRock board has ALC 897 which really isn't top of the line either, and I'm going to assume this is the same as what is used on the ASUS board as both are Realtek 7.1 from the same Gen and when using a premium codec they will usually make sure you know it. A push here so to speak.
Both also have BIOS flashback.
So the only thing that really stands out between them is a seemingly better VRM on the Lightning, and an ASUS board that definitely is more attractive, in a rugged way, than this ASRock board, in my opinion. Different people different tastes though.
In truth, price and personal preference are probably the deciding factors here as both boards likely have similar features and performance with that CPU.