Don't get fooled! What some sell you as "6K" and "7K" is nothing but a marketing magic.
Both ZCam K1 Pro, K2 Pro and Go Pro rigs used to shoot 180 stereo porn are capable maximum of 5400x2700px 180º stereo. Everything else is upscale with no value in visuals, but bigger filesize and required processing power. You might ask such producers directly about that and refer to this post.
You might appeal there's a difference in visual quality from different producers, but it's not because of resolution, but of other things.
One 6K producer has very good light. The image quality there comes from the light, not because of 6K. Originally it was shoot in 5400x2700
There's one "7K" producer now and K2 Pro use to shoot these videos has a different sensor than K1 used for "6K" videos, while the same 2700x2700 output for an eye. There will be some few producers using this camera once lockdown is over. Everything to be released in original 5K. To give a little more of explanation the sensor's RAW is 3696x2772, but only 2700x2700 could be productively used like on the photo https://i.imgur.com/aNsJK1j.png (actual K2 shot). No matter how wide you make it, it will still be cut to 2700 vertically.
That way "6K" or "7K" resolution is just a decoration, it doesn't hold any real value.
Having these videos in 5K would not change perceived quality in a bit. As immediate outcome you are consuming more bandwidth and processing power to download and decode these.
I would suggest it mandatory for every studio promoting 6K/7K to disclose if it's upscaled. It could be proven they aren't upscaling by posting 3K or 3.6K sensor image like above. There is no secret tech in it. Everything else is an upscale