I encode everything with AV1 and Opus, although, as others have pointed out, there is the disadvantage that older (as in “not new”) devices won’t have hardware acceleration for those. I don’t care about that tho, because 1080p runs just fine on decent CPUs and I want to encode for the future, not yesteryear.
For AV1 I use 10bit, VFR, RF25. If you want, you can play around with the performance profile to trade file size for encoding speed.
For Opus I use 320 kbit/s fixed Bitrate and 7.1 downmix. Note that when dealing with audio and subtitles, you absolutely should include tracks of ‘unknown’ language! Otherwise they are just thrown away. And of course you should include every other language you care about. You can also choose to pass through Opus encoded tracks automatically.
I prefer MKV as container format, because from all I hear it’s flexible and robust. Pretty much everything else is set to default. I’d advise to safe your settings to a preset and to briefly verify encoded videos actually work and contain the desired tracks.