Phase shifting vs Extraterrestrial

What if all these UAPs are not from far away distances? What if it’s simply impossible to go from one star system to another and travel faster than the speed of light? What if that’s really the limit and life doesn’t travel from place to place in the stereotypical manner like our blockbuster alien invasion movies depict?

For the sake of this conspiracy theory, what if we’re limited to travel in our own solar/binary/poly star system and massive distances are simply, impossible to transverse?

If we assume that basis is true, while giving some extreme flexibility about assuming UAPs are real and are not of this world, what would they be?

Perhaps they’ve always been here, a self replicating drone/organism left from a previous civilization on mars with the only mission to preserve life and prevent the atrocities of their past from happening again via preventing nuclear winter?

Or, instead, what if our visitors are actually phase-shifting between realities or parallel universes? What if there are countless iterations and each one is different from another, a la Rick Sanchez minus intergalactic travel and flippant use of a portal gun?

Maybe it takes a huge amount of concentrated energy to disrupt and phase shift while limited regarding what you can transport? Maybe a parallel reality is 200 years ahead because of some minor difference that cause them to conquer a technology that would appear as magic to us?

Just shooting from the hip here, having some good old conspiracy theory fun.