Trying to be vague to avoid spoilers, all I can safely say is the scope increases massively after book/season 6 and it's a shame they won't make it. There is a 30 year time jump but it wouldn't be too hard to deal with aging prosthetics as this is a time where folks are living to 150 odd years so the physiological changes wouldn't be massive.
Books 7/8 and 9 when it releases basically really go into the who/how/why of the protomolecule, worlds beyond the gate, what happened to the builders and something massive I won't spoil here. There is now way to bring that forward into next 1.5 seasons.
I think more is going on behind the scenes as this time last year, the showrunner believed they could handle the time jump. Link has spoilers.
https://www.cinemablend.com/televis...zon-show-can-pull-off-massive-time-jump-ahead