Ask HN: Proportional Coding Font with Ligatures?

I really like Iosevka Slab and Fira Code as coding fonts, especially because of the nice coding font ligatures, where, for example, != is changed into ≠ and => becomes a 'fat arrow'.

I just tried coding with a proportional font (specifically, Optima), and it is lovely to look at and work with. But, I'd really like coding ligatures and, say, more pronounced brackets and braces.

Is there such a thing? [Alternative, how would I adapt something existing to accomplish this?]

[Yes, I understand that many people don't like non-monospace fonts for coding with. That's fine, you don't have to like it. I do think good support for Elastic Tabstops ( http://nickgravgaard.com/elastic-tabstops/ ) would get rid of one of the best reasons to use a fixed-width font, which is otherwise often the only way to align things.]