AMD is not really on par with Nvidia for H265 (NVENC vs VCE).
Hardware Encoding 4K HDR10 Videos? - Code Calamity
Compare how the three GPU industry titian's HEVC hardware encoders compare to x265 and if it's worth using for encoding your videos!codecalamity.com
And looking at the certified software list, Blackmagic (Davinci), Adobe etc do not feature in the listings: https://www.amd.com/en/support/certified-drivers
All my exports are H265 (NVENC), super fast to encode and the quality and motion is near enough identical to the source format whilst the file sizes are massively smaller. So for me that's a win win lol.
Personally not used OBS, but do use Geforce Experience for all game recordings, then transcode to H265 NVEMC using Handbrake if I decide to keep any footage or upload to youtube etc as the quality is the same, file sizes more than halved. Encode speed is typically 150fps+
Isn't VCN the old version of AMDs codec which wasn't great.
I thought it was AMF these days.
Testing Shows AMD's AMF Encoder Finally on Par With Nvidia NVENC
Update introduces sorely needed b-frames.
www.tomshardware.com
You are right, Resolve doesn't yet support AMD Hvec for encodes, only decodes, hopefully we see them update it for AV1 like they have for Nvidia, not sure about intels offerings for that.
OBS lets you record directly with Hvec with nvenc.
Honestly, with the amount of people dropping Adobe, I reckon they will have a hard time, esp since Apple dropped Intel which really hurt them.