we exist in mutiple dimensions simultaneously... only we are restricted to our perception of it.

Yes, you're welcome. That's a very good statement of it. The spirit (and soul) have a dimensional experience that, although usually (not always) localized to our position in these three dimensions, also range widely in other dimensions. Some of your other phrasing is not exactly the way I would say the math because all dimensions operate at the same spacetime instant and time is its own dimensional set. What current science is doing is treating time and space as isomorphic dimensions, which is what makes time "irrelevant". So by "time travel in 3D" you are presumably talking about moving the atoms from one time to another; and (since that happens all the time in the time-arrow direction at one second per second) you're looking about moving them at other rates than one second per second. That indeed has its difficulties, and most time travel fiction is actually about multiverse manipulation because it's easier to write about that and call it time travel when it isn't.

By "interdimensional" you are presumably referring to the wormhole connections that allow time travel of the bits (the information) without having to move atoms at macro levels. This kind of time travel is very efficient and meets most needs of time travelers, but it doesn't "change history" because history is one when only one universe is reified. To "change history" you need a multiverse, which is a separate discussion entirely, though the tech is related. You also have teleportation without more than ordinary time travel, which is another tech again.

Now the beings we're talking about do have some time-travel tech at the bitwise level because they are experienced at describing the extra dimensions and we're not (we've relegated it to our language of legend, imagination, and seeming). It's only since Lorenz, Planck, Einstein, and Eddington that we've made any sense of it at all mathematically, and our understanding has been thwarted in part by the cabal. But the good news is that when we need time travel, the time travelers that exist across past, present, and future, have helped us with the amount that we've needed (without breaking prime directive). That's what my own disclosure has been and will be about, and that's what the US's official UAP disclosure (checks watch for tense) will be about. Time continues passing but for it to pass requires change and the trick is reframing the change that's being used to impart the feeling of passing into the sentient being. For that we have what we need, and so I trust the actual time travelers who are moderating the holding off on the UAP disclosure for now, even though I don't know exactly how many there are or how much pull they have versus the greedy rogue elements that just want to mine UAPs for unobtainium.

As to evolutionists, they often assume one planet speciating another (panspermia), but the problem is that this is as equally impossible via the math in this reification that the expected number of species is still zero. My point was that neither our species nor the one or more that we experience evolved from another such one; the only way to get one is to use an assumption that explains fine-tuning, and once you've done that you can also tune the number of intelligent species to any reasonable finite number. What's more reasonable is to assume that a species that we've encountered for millennia is one that already has traffic here rather than that has to have an origin somewhere else. Lately I've been working the track of other ETs, and I finally found a way to allow literalist Christians to let them into a backdoor, but they don't seem to be significant in the UAP question. If they're not one of the species that has/have been manifesting already, ultimately their species would become a party that would enter on the side of one extant species claim or another. Sasquatch Wars.