"But existence may include things that exist but are not in that frame at all..."

ahh... that sneaky word 'may'! I don't even know how to approach asking in what sense 'exist' has meaning when we try to discuss such 'maybe' realms. Are they dependent on 'us' being here to conceive of them? Did/do they 'exist' prior to whatever went 'bang'?..(IF something went bang)....etc. ∞∞

Asserting such things in such realms is to me, (as you know), very little different than asserting and defining 'heaven' or 'god'. I can explain experience of such realms in ways (as you also know) that don't require as many premises....but my real point is that we can't really DO anything but assert and counter. My solution, such as it is, is to shrug and say, like the old man talking about modern songwriting, "Why, they're just singin' about air!"

Seems like we get into this regularly, hmmm? Maybe we oughta do like the old line about jokes and just number our assertions and rejoinders?

"Hey...that a #7!"

"Oh, yeah? Well # 14b to you!"

"Hummmpff..you are just #11ing!"

"Well, at least I don't #43!"

'twould save lots of typing, and the reaction of bystanders might provide some amusement....