Heyo FlyinGroundSalad, do you normally have issues rendering new maps? Did the map ever lag before you tried exporting an updated version? What are the dimensions of the map, and are there any new particles? I expect you have already placed the objects used into their own custom groups and have no issues with them considering you have used the map previously without issues.
In all honestly, removing the new objects you have added, keeping the new portal, and just re-exporting (in a fresh FH download to avoid any issues) would probably be the way to go. From there you can just keep adding objects until you are satisfied with the map. If the issue does not resolve on its own, if you would like, I could try exporting the map if you send me your whole media folder privately.