'Lightweight' encoder for high bitrate video, 60 FPS, YUV444?

[antoniu200]

retail mpeg-2 uses 4:2:0 so 12bit of raw information.
4:4:4 is 16bit data. So just sticking with 16bit increases the data that needs to be saved by 1/3.
Additionally, more than doubling the amount of pixels and increasing the frame rate also requires more data.
-> so be aware that lowering the options of the encoder might work against your resulting file size.

I just did a calculation. 1360x768x60x16 is actually above 1920x1080x23.97x12. And here I was thinking I was far below what Blu-ray has.

Well that changes things.
In that case, I'm ok with losing some quality as long as I can encode fast enough and keep the bitrate under or equal to 20M.

The complexity of the format doesn't really change.
What is your goal in lowering complexity?
Getting faster encoding or faster decoding, or something else?

Faster encoding, so I get less lag in games while doing so.

Ryzen 5 5500 + Geforce 980, so hardware encoding isn't that interesting. (Hardware encoding without b-frames is often worse than using x264 with ultrafast preset.)
-> Have you tried x264 and x265 in their ultrafast presets and adjusting quality through a lower/higher crf value?

Not until now, here are my codec options (using OBS to setup FFmpeg):

preset=ultrafast profile=high444 crf=17 tune=zerolatency maxrate=20000000 bufsize=40000000 pix_fmt=yuv444p hwaccel=auto opencl=true force-cfr=1

Unfortunately, with these options, the bitrate reached 44M at some point. Or is maxrate ignored when using CRF?

The CPU usage remained relatively low, 10% max. Also, with these options I think it's relevant to say B-Frames are also turned off.

EDIT: Forgot to mention, keyint is 600.