Help hooking up a laptop up to a tv

Hey I am having issues connecting my 2018 macbook air to my 2018 LG OLED. Since like 2010 I've been using a mini display port to hdmi adapter to connect my mac laptop to my tvs, never had an issue. I recently bought a new adapter and new hdmi cords (links for reference below) and it's not working on my LG TV. When I plug in the adapter with the HDMI plugged into the tv, a message pops up in the top right corner of my tv that says "HDMI 3 now available" so it recognizes something has been plugged in, but when I go to input 3 it says no signal. If I go to system preferences and display on my laptop, nothing shows up as a potential second screen (detect displays does nothing).

I've tested every HDMI port on the TV, tried every other HDMI cord I own (both newer 4k compatible ones and ones I've had for 8 years) with no luck. I tested the adapter and hdmi on another tv (Samsung) and it works there so I don't think it's a failure with the laptop or equipment I have. I've also looked for and tried every "you won't believe this trick works" for this problem including power cycling the laptop while holding these buttons, restarting the laptop and closing it immediately, shutting the tv off plugging in the cords in a particular order etc. Don't know if there is something I am simply overlooking but any help or input would be appreciated. Do I just cave and get a apple tv? Can I just airplay my computer to my tv with that?

Thanks


https://www.amazon.com/gp/product/B07H76P2XG/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B074FFM8NH/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Check the video display settings on the laptop, might need to extend the displays or add the tv as a second monitor. I'm a windows guy so I'm not sure how that works on a MacBook, but that's how I get my windows laptop going on my tv it has to a similar setting somewhere on the mac.

Have you used the adapter on a 4K screen before?

@evisceratingaxe: I have not.

Is this the newest Air or the previous model?

I would try changing the resolution in the laptop settings. It's possible your TV just doesn't support the native resolution of your laptop - which would be 1440x900 for the non-retina Air. Bump it down to the next lowest resolution and see if that works.

Was your previous adapter an active adapter? The one you linked is not. Sometimes the adapter needs to make the conversion itself, and that's where an active adapter comes in. I'm not recommending this particular one per se, but here's a suggested link from the adapter you posted above that is active.

https://www.amazon.com/Cable-Matters-DisplayPort-Supporting-Technology/dp/B00PJ3LSIG

@thornghost: Yes! After after doing more research, apple display ports don't support HDMI 2.0 (or something like that) so I got an active adapter that is supposed to work with 1.4 to 2.0 and fix this problem (not this exact one but it seems to do what this one does). I also downloaded SwitchResX and am playing around with that which lets me manually push up the resolution so my tv can display my laptop. Thank you for the link though, I spent way too long trying to find an answer to my problem and it looks like this kind of adapter is it.