Can we use "so" in negative sentences to mean "very"?

Question

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.

Answer 1

I'd never really thought about this one before now - but this mixing of 'so' and 'very' is very much a non-native 'tell'. Natives do it without thinking, of course, so when a non-native has to choose which to use, it's very noticeable to a native if they choose the wrong one.
So, how to pick which one?

This is the conclusion I came to...

You can use 'so' to mean 'very' but not always.

In a simple statement it works well.

Oh, this food is so good.

But in a lot of cases there is some element of comparison, which 'very' doesn't have.

Think of 'so' as having some kind of limit, some quantity or quality which is unstated but has a kind of invisible count.

I like it so ||||| much.

I don't like it so ||||| much, I only like it this ||| much...
That's not so ||||| much as if I liked it very (|||||||___) much.

'Very' doesn't have this 'count' or 'grade' hint to it, it's just 'a lot'.

I thought their last album was very good, but this one is not so good.

'So' in this last case has an 'invisible count' of whatever 'very' had just before, but failed to match up to that count.

Their last album was very good but this one is so much better.

Again, we've somehow quantified an uncountable 'very', put a value on it & made 'so' more than that.

Even if there's no value to compare to except ... life itself...

I don't like this sandwich so much

that's really comparing it to all the other sandwiches you've ever had, putting a value on them, then measuring it against your current sandwich's 'score'.

Answer 2

Yes. The +/- aspect of the adjective doesn't matter in the use of so vs. very.

That's so disgusting. / That's very disgusting.

Are perfectly fine forms depending on the situation.