Online gender tests are a bit of fun but they should be taken with a pinch of salt. There is no substitute for assessment by a qualified professional, IMHO. That having been said, every single online test I've taken has agreed with those qualified professionals' opinions.

I ought to point out that the S.A.G.E. in particular takes your physical appearance and birth sex into account, and it can
trigger dysphoria if the results say that you look like your birth sex. My results say that my appearance is 'Feminine', even whilst acknowledging I've taken steps to present as male. Ugh - what a terrible word to choose!!!!! Some MtFs are described as looking 'Masculine', which could obviously trigger similar dysphoria.

It analyses my socialisation & thought processes as masculine... but because it describes my appearance as 'Feminine' (due to my face shape) it calls me Androgynous, which I find frustrating. Then they put the bit about me being born female in bold letters, just to make sure I don't miss that little fact. But then it later goes on to correctly identify me as FtM in transition, with major conflicts about my gender identity.
So whilst these tests can be fun... the main reason why people tend to do them is because they
already know they have questions about their gender identity.