in theory i guess you could export the height map, increase the size and then import it again? but i’m not sure if you’d have to start again from scratch to get this to work, sorry
A heightmap is just the terrain, and frankly that's just a little bit of the work you will have to do. I know Simsupply has answered this question before, so a search in this subforum might be a good idea.
Thank you for your help. I'm a dummy for not looking on this forum more. Aka I googled my question and came up with nothing hence my post. I did figure it out though by following this post if anyone else is curious: https://modthesims.info/m/showthread.php?t=453513. I simply opened a large world in S3PE and the world I wanted to expand (small world) then copied the files stated in the post from the large world and pasted them in the small world file and bam. Expanded world with all the lots and objects still there. Only catch is the terrain because I used a flat map therefore all my terrain was flat so I had to resculpt the terrain. However, it beats having to restart and having to replace everything if I reworked the heightmap.