I'm a newbie, so while waiting for someone far more knowledgeable than I to respond, have you tried recording to MKV instead (search the forum for LOTS of threads mentioning this, and why). Also, due to the mess that is licensing around HVEC/H.265, have you tried H.264 instead? I totally get wanting to use the newer, more efficient codec, but the licensing scenario is such a mess that companies are bypassing it. So it may make sense to record in MKV with OBS, then do your editing in Resolve, and re-encode there?