I make gaming videos, I usually record them with a very high bitrate (nvenc h264) for the best quality at 200+ mbps, and then convert them with ffmpeg h264.

I would like to know which preset can give me a lossless quality and smaller size? I have been trying to use CRF 15 with placebo and tune grain which is very acceptable but not lossless and takes too much time. (it gives me a bitrate between 35 mbps and 65 mbps)
While tune film is giving me half bitrate of what tune grain does, the quality is a lot worse.

It's a waste of time using placebo compared to veryslow? Is my CRF too low? But sadly from my tests, if I use a higher rate like between 18-20 I can see the video starts to lose some details.
Also the in-loop filter I don't understand how is supposed to be used, I'm using a value of -2 currently.

I don't know if resolution matters, but I often use 1440p and 1080p, here's the media info:

cabac=1 / ref=16 / deblock=1:-2:-2 / analyse=0x3:0x133 / me=tesa / subme=11 / psy=1 / psy_rd=1.00:0.25 / mixed_ref=1 / me_range=24 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=6,6 / fast_pskip=0 / chroma_qp_offset=-4 / threads=9 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=0 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=16 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=60 / rc=crf / mbtree=1 / crf=15.0 / qcomp=0.80 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.10 / aq=1:0.50