H264 or H265 are acquisition or diffusion codecs, never were they intended to be editable natively for that matter.
Offline editing may not be always the fastest solution but it really is the best way. Managing media, transcoding, conforming, knowing the difference between working formats, and acquisition/diffusion format is a lost art, and it's a shame because in many situation it actually is the simpler process in the end (even if it doesn't seem so at first).
If H265 not being an editable codec is the only thing preventing you (noone specific in mind, you the average reader i mean ;) ) from buying this camera... Buy it ! and learn how to deal with these situations, it will only make you a better editor, a better image technician, it will teach you professional workflows... It's a win-win really ;)