Is it possible for me to change the metadata of an nft that i own but am not the creator of? Like can i change the image it is linked to and the attributes along with then freezing the metadata?
No. In the standard usecase (ERC721) ownership of a token doesn't give you any extra priviledges. Only the owner of the NFT can ever change the metadata of your NFT.
The weak point would be to 'hack' the centrallized service that hosts your metadata and change it on the same url, which is unlikely.