This topic had been asked several times. I suggest to use the search function to read previous posts on it. In case it would be too fiddly here, use google search with including the keyword " site:cbr500riders.net " and searc for words headlight round swap change or similar.
It has been brought up several times, but I haven't seen anyone follow through with it. I found a few members that did headlight mods, but not like Joe is talking about. There's the MAD CB500S concept, which looks awesome, but a lot more went into that than just the headlight.
My Ideal first bike would be a cb500r, but it doesn't exist. So my plan is to buy a 2018 cb500f, and swap out the headlight for a more classic round LED headlight. I basically want to take the headlight from a cb300r or cb650r, and put it on the cb500f. How difficult would this be? Should I get an aftermarket round light? Or would it make sense to get an OEM Honda headlight from different model (from a 2019 cb300r, for example)?
I wasn't crazy about the look of the CB500F headlight at first either. I'm still not crazy about it, but it's growing on me a lot more since I added the Puig Naked New Generation windshield. I looked into what it would take to swap the headlight, and I ultimately decided it wasn't worth it. There's too much integrated into the front fairing. It would require a lot of cutting into the factory wiring harness to make it work with anything aftermarket.
If you're looking for something that's plug-and-play, you might get lucky piecing together parts from other Honda bikes. I'd look at the 17-19 CMX500, for starters.