We recently had this done downstairs in our property by
https://www.soundproofingrus.com/pro...ategory/walls/, and, by an odd co-incidence, are having our upstairs walls sorted this coming Monday.
Not cheap, and you will lose some room space dependant upon the option you go for, but the results, for us at least, were well worth it. I appreciate what you say about the door issue, but it may nevertheless be worth giving them a call to see if they can help with a solution for your particular circumstances.
Cliff