Connect SEGA Mega Drive 2 to smart TV
I would connect it in this way. The Video output of SEGA Mega Drive 2 would be connected to the Video(Y) at the back of the TV and the audio out of Sega would connect to White Audio/Mono socket at the back of the TV.
A simple dual-RCA cable would suffice in this scenario. The console outputs a mono channel sound-stream, and your TV has provision to accept exactly that.
Looking at the back of your TV, I don't see why you can't just use normal RCA cables. The yellow cable (video) would plug into the yellow/green socket, and the red one (audio) into one of those red sockets (not sure which). Alternatively, you could get an RCA to HDMI converter like the one below. This would require a separate HDMI cable, and an RCA cable. You will also have to power the unit externally. This one is powered via USB.
Experience wise - I don't think you'll gain much benefit by using one of these methods over the other. Maybe a bit cleaner of an image via the HDMI connector, but I'm not sure how the converting scales.
Edit:
I can't tell for sure, but some sites and videos seem to suggest that you need to use the RF Wire port seen on the back of your console, and an RF Unit supplied with the console like this one. This unit would then connect up to the antenna socket on your television, which your television does have (next to the Cable In socket). I'm not too familiar with this console, but I can't imagine the RCA connections not working for this since that is how RCA cables work (at least that's how it worked for my old Sega Saturn).
Side note - looking around at images of the Mega Drive 2, none of them appear to have RCA connections at all... which confuses me as to why yours does.
As I can see from the picture, your first RCA connector is half green and half yellow, this means that it can accept both Green component either Composite video.
Most of the AV devices uses to accept mono audio on the left channel input.
Said so you can just connect Mega Drive Yellow to the Yellow/Green RCA and the Red one to the white one using an RCA Male/Male cable.
Just bought a megadrive 2 to resell and tested it using Red wHite Yellow cable RCA to AV cable. Sound works fine but black and white graphics. When using the original RCA cable that has the ANT RF switch sound is white noise and the graphics are great and in colour.