Sorry, but it seems to me that the palm tree generation system is illogical. Is it possible to change their generation so that they do not appear near the ocean in a snow-covered biome? And in other biomes where it does not combine

I see where your problem is, I sadly can only check within the Chunk the Tree is generating in, I might be able to put in some sort of blacklist for if a bad Biome is within that Chunk, but even then it is not guaranteed to work.