INTJ for me, no matter whose version of the test I take, so I accept that's what I am. The spectrum is very broad though, and we are often good at disguising how we feel, so it is not surprising that you feel it is inexact.

Someone on this site referenced Quiet Revolution as a resource for what you're asking: [quietrev.com] I don't know of anything else other than a lot of pop culture tests that are just click bait for ads.

For me it’s all about energy. Being around people is physical and mentality draining. Where as an extrovert gets energy from being around people.
While I prefer to be alone I do enjoy the company of certain people. I enjoy talking but not to people. While I do crave company social anxiety along with the thought of how drained I feel after makes me not want to. But this is just me personally.
Also it’s possible to be outgoing and be an introvert or shy and an extrovert.

I have taken personality tests from the organization Individual Differences Lab. In addition to myers briggs, this organization also has its basis Carl Gustav Jung. They are fairly accurate (INTJ for me).