I'm using (Almost) No Height Limit and Continents with Tectonic because i noticed in a previous copy of the world the tops of the mountains were getting cut off, so i installed the height limit mod which i expected would fix it, but it is still an issue. Is there a way to fix this on my end, or is it some kind of fundamental limitation that I can't get around?

Almost No Height Limit is not compatible with Tectonic. If you want increased build height, turn on increased_height in the mod's config file.