I know that in positive sentences we can use "so" for meaning "very". For example we can say "The new Slipknot album is so nice!", "I practice guitar so much.", "I like them so much.", "I can play that game so well." etc.
So, my question is: Can we use "so" in negative sentences too with the same meaning? I think in the sentences like "Don't be so stupid." and "I never felt so good.", "so" probably always means "this/that" (as great, nice, many, stupid etc as this/that) instead of meaning "very". Thus, "Don't be so stupid." means "Don't be this stupid." instead of "Don't be very stupid." and "I never felt so good." means "I never felt this good." instead of "I never felt very good.". But let's make up some other negative sentences that include "so" along with the contexts where we can say them:
1) Let's say we were not talking about music, but my friend wanted start a new conversation topic and asked me: "Did you listen to the new Slipknot album?". As an answer to that, can I say "Yes. It is not so nice." for meaning "Yes. It is not very nice."?
2) Let's say somebody again wanted to start a conversation about music and said "By the way I recently started playing guitar. It is so difficult." As a response to that, can I say "I recently started playing guitar too, but I don't practice so much. I need to get more disciplined."? I used "so" for meaning "very" here too.
3) Say, somebody said "Do you know Duran Duran?". Can I answer by saying "Yes, but I don't like them so much."? I am trying to mean "very" by using "so" here as well.
4) Let's say somebody said, "How good are you in the last Call of Duty game?". Can I answer by saying "I can't play that game so well." for meaning "I can't play that game very well."?
Probably, we can do that (we can use "so" for meaning "very") in these four instances I gave and in the instances similar to them. I found results on the internet which show that as well. This scene from a Marvel movie is one of them. Or does "so" mean "as great, nice, many, stupid etc. as this/that" in those four sentences just like it does in the sentences like "Don't be so stupid."? I am not sure. I'm really confused, so I need your help.