for windows 10 there is this app to delete the chunks http://www.mcctoolchest.com/Download it took me about 6 hours to delete the chunks and keep my buildings in the overworld and nether and have it create the new structures.
to correct this problem I have to delete some parts of my map in the nether and overworld making those parts update to the new version
take a look at this picture I sent is something like that?
sorry for the inconvenience these bugs were from a certain version a few years ago of that map i'm not sure which one was more in this version 1.16+ this problem does not occur and if it was due to some old version of the game that was affected. I really wanted to erase this pending but I don't know how I do it. thank you.