Go to a physical showroom with your best sitting pants and a bag lunch. No one here could possibly know what ”is soft but not too soft” for you.

I'd visit IKEA if there is one near enough. They 'rate' softness levels for you and favor low prices and modern silhouettes.

You are going to have to actually spend an afternoon or several afternoons actually test driving sofas in person because one person's comfortable sofa is not necessarily another person's.

What you can do on the internet is look at all possible furniture stores in your area including the major players like Restoration Hardware as well as local ones and see what styles you like and what the price range is for their sofas. That way you can at least save time by only going to stores that stock styles that you like within your price range.

At that short length. It's basically a love seat /settee : )

COMFORT? WHO KNOWS???

Go shopping.

For a sofa that short you're looking for an apartment-size sofa. Crate & Barrel &Pottery Barn carry these types of sofas.

I can't speak to the comfort, but Room & Board has the Astaire which is modern and curved. Unfortunatley not under $2000.

The 74" modern sofa has some curvature. You can get actually curved modular options if you to up to 100".

https://www.roomandboard.com/catalog/living/sofas-and-loveseats/astaire-modular-sofas

Or there's a bench seat version as well.

https://www.roomandboard.com/catalog/living/sofas-and-loveseats/astaire-bench-cushion-sofas