Top tube length is the critical measurement- not seat tube. You can raise a saddle with a longer seat post- and you can extend the length with a longer bar stem.

I am 5'6" with a 30" inseam. I like a top tube length of 53.5cms. but my first road bike was on the short side. Adapted it to fit me but that was compact frame that covered from 46 to 51cm. I Now ride a 51.

Attachment is of the bike that is too small for me- or is it?