I think the boring answer is that the people who are looking to procure B2B SaaS solutions aren't looking for artistic sites that "evoke" a feeling. They're looking for a product that meets their needs, and one of those needs is "when I tell my superiors / peers / users about this product, and they Google it, it looks crisp and professional, like giving this SaaS a big stack of money will be worth it."

The answer to your question is ShadCN

Evoking a vibe is what artists try to do. Visually enticing buyers of your product is what graphic designers do. Either use a designer or copy from the millions of expertly designed sites that already exist. You'll have to change it all anyway in a decade or two when styles and fashions change.

Orienting according to look & feel patterns that people are already familiar with are always a good thing to follow: Like "X" for closing some object usually on the upper right etc.

People actually decide if they like to use an app if the adaption to the usage of that app is as low as possible, so copying existing patterns is good practice.

pattern matching. if you stray too far from the group, procurement folks get jittery about needing to explain it to their company.

well, listen to the users.

The UI matters A LOT. We are the creators who know the product inside and out to the last comma in the code. This makes us completely blind to what our users actually see.

We design our UIs to be functional, because of the aforementioned. But the users have absolutely no idea what is going on under the hood. The UI is THE product to them.

So as a fellow founder/architect/... i strongly urge you to hire a professional designer who will create a CONSISTENT and INTUITIVE user interface. YOU will not see much value in that but your users WILL.

Personal anecdote, when I launched my last project, Gethly.com, I asked a friend to do some user stuff and give me some feedback. I very quickly realised that I had a lot of work ahead of me when he told me he had no idea how to do absolutely basic things because of the wording used in the UI(nomenclature can become a problem) or click a link that was staring him right in the face was completely invisible to him. Again, I call this "founder's blindness" type of thing where we are incapable of seeing our own work through user's eyes as we have too much knowledge of the whole thing and cannot even comprehend how someone would be unable to do a, in our eyes, most basic thing.