Combine -vf yadif,format=yuv420p and -filter_complex for watermark
Use

ffmpeg -i input.mp4 -i logo.png \
-filter_complex "[0]yadif,format=yuv420p[main];[1][main]scale2ref=iw/5:ow*450/450[wm][vid];[vid][wm]overlay=W-w-W*3/100:H-h-H*1/100:enable='gt(t,30)'" \
-force_key_frames "expr:gte(t,n_forced/2)" -c:v libx264 -crf 23 -c:a copy output.mp4