The difference between reincarnation in the 3D physical
world and ascension to 5thD crysta-physical world's and beyond is that reincarnating within 3D timespace is a progress wereby one expreinces lifetime after lifetime in linear fashion.

Those who are 5D+ at their very core are beyond 3D linearity of lifetimes experinced in and out one after the other

Instead their 5D+ omniscient soul experiences all alternate cosms of their lifetimes simultaneously and when they die they ascend either which way... Whilst 3D souls (people who have not learned all the necessary lessons to remian in 5D) live linear incarnations for as long as they choose and each time, until they experince nonlinear enlightenment of 5D awareness

All possibilities manifest simultaneously in the 4th/5th D
choice is what makes the path one chooses come true the right to ascend via the non-linearity of 4D is acquired after every life time of an infinite many that has already been lived via 5D omni-soul aspect in the 4thD as simultanoues manifestation of all moments at once. So once one reaches the singularity point they are shifted into the quantum time-line-series of possiblities which yields to their physical ascent. This is where the individual experinces deja vu-like overlays of of alt lives lived - the singularity transcends the 3D quantified timespace boundaries of alt-cosmoses – an omniscient merging etc of all their experiences which are truly desired.

Some people are preformed as transcendent souls before entering the 3D so they have no lessons to learn (omni-soul 5D+ nexus) and they have been conduits to teach others the way. Some of them may not experince a smooth shift of physical ascent due to trauma in the 3D which is cuased by being an omnsicent empath of what others have exprienceing – keeping them form being receptive to the graceful shift in the now and will ascend to the 5th D when their 3D body die's – however many do not recognize when these events of 3D death occur becasue the timelines where doom occur's are lived as accelerated dreams in an instantaneous fast-forward blip and the memory of truma is erased upon waking into a alternate cosmos of higher potential.

Sometimes this may happen when wide awake aswell and thats when one experinces an alt-cosmos seep through as an overlay or a blip like an accelerated dream vision in the 3rd eye whilst awake, essentially one is awakening into the cosmos of which one has memorey retention of – it feels like one has always been there and lived the line of accessed memorable events but in truth they have passed from an alt-reality and that part has merged and become aware of all past moments of the self which always existed in the new cosm... this is felt as a form of pristine relaxed deja vu – other types of deja vu are more divergent and not identical overlays, there will be discrepancies and one will still have a sense of anxiousness and trauma thjis will resolve in the dream state