Interesting question for sure. Let's reframe the question into terms that have been dealt with in this context. You're basically asking whether the mitzvah of simcha (rejoicing) on Purim is (A) objective -- you need to consume meat and wine at the Purim meal, and if you can't for medical reasons, you are exempt and there is no substitute; or (B) subjective -- there is a mitzvah to rejoice, and what makes you, personally, happy (i.e. whatever "floats your boat") fulfills that obligation.

Now on a regular holiday (yom tov), there is an obligation of rejoicing (simchat yom tov). Purim is not a yom tov in the technical sense (there is no prohibition of labor, although we generally don't work on Purim), but there is an obligation of mishteh ve-simcha -- feasting and rejoicing. Bottom line, rejoicing (simcha) on Purim is similar to and analogous to rejoicing (simcha) on yom tov. The basic difference -- the amount of drinking is augmented on Purim (ad de-lo yada etc.).

Now in the case of simchat yom tov, there are two components. The basic mitzvah is eating certain Temple sacrifices (shelamim, Pes. 109a). This is an objective requirement; that is, it doesn't matter if eating those sacrifices makes you happy IRL; the mitzvah is to eat it. But some say, there is a second component to simchat yom tov and it's subjective: you have to actually be happy internally, in your inner being; you have to rejoice IRL, in addition to eating your sacrifices.

That brings us to today. We have no Temple and we have no sacrifices. So how do we observe rejoicing on a holiday (simchat yom tov) today? Answer per Rambam: we eat regular meat and we drink wine (Rambam Hil. Yom Tov 6:18). So the question is: is today's eating meat and drinking wine (A) a substitute for the objective "rejoicing" -- i.e. a replacement for the sacrifices that are missing; or (B) an expression of inner rejoicing -- i.e. subjective rejoicing only, because the objective "rejoicing" (sacrifices) is gone? There are two views: some say A, some say B.

This brings us to your question regarding Purim. If our rejoicing (the Purim meal of meat and wine -- see Rambam MT Megillah 2:15: "How is the obligation of this [Purim] meal? That one eat meat and prepare as pleasing a meal as his hand can [afford]. And he should drink wine until he becomes intoxicated and falls asleep from his intoxication.") is a substitute for the objective rejoicing of eating sacrifices in the Temple on a holiday, then there is no acceptable alternative; but if it's an expression of the subjective rejoicing -- whatever makes the individual happy -- then "whatever floats your boat" should be ok.