MMaRsu,
ok, so basically this is what I found worked best on the LG C series tv. I turned everything off because I always turn everything off on tvs (energy saving is especially important since it limits OLED pixel brightness). Then I used this chart from Resetera, from this thread.
https://www.resetera.com/threads/lg-2017-2021-oleds-suggested-settings-for-xbox-one-series-x-s-ps4-ps5-and-webos-sdr-hdr-dv.73304/Someone said the variance in a bunch of LGs they tested were like 3%, so even though yeah to get absolute perfect calibration you need to spend $500-700 on tools and do it yourself or hire someone, you can get a pretty fucking good picture using these and just tuning slightly to how you like it by eye.
You want to pick a mode and set SDR sets and apply to all inputs and then pick a mode when in HDR and set all settings and apply to all inputs. HDR doesn't need much tuning, SDR needs a lot. Important to set your black level to LOW/LIMITED on both console and tv to get full range of black which makes no fucking sense to me why limited would have a wider range of black level than full wtf.
The only thing I'm iffy on with those recommended settings is they keep sharpness at 10 whereas I've always been told to put sharpness at like 0 for all TVs and some movie stuff seems a bit sharp. I might knock down to 5 personally.
Also keep in mind that after you put those settings in you want to run the console's HDR adjustment.
Also the specific game settings are really helpful. Like AC Valhalla looked way too dark on the HDR settings default but I boosted HDR nits from 600 to 4,000 and exposure to 0.5 like recommended and it looks just right. Very few games have built in HDR stuff though.
Anyhow this isn't 99% perfect calibration/quality, but it's a very good start and makes most things look rad. Also it's good to know that OLED Tru Motion on games doesn't fuck with image quality and just changes how frames are drawn so they're drawn closer to Plasma/CRT and you don't get the slight motion blur on movement. The downside is you lose a lot of OLED pixel brightness. But on some games if there is excessive blur that is distracting (like say a racing game when you turn) having the option to get rid of the blur at the cost of some brightness is good to have.