Basically every significant app you interface with is designed with Figma at this point.

Figma itself has no opinion about the resulting UX. It's a tool for designers, and they can design great UX, horrible UX, and everything in between.

Your question is kind of like saying "I want to see a house built with a hammer, to see if a hammer makes nice looking houses".

You wouldn’t really be able to tell. Figma is often just a tool for working out designs and building up a design system for your site. That later gets translated to your front end by your devs. Figma itself isn’t a styling library like tailwind, etc.

But are the designs lean or bloated.

If Figma helps building lean designs it's good otherwise not.

Designers tend to put too much useless parts into sites, like unnecessary transparencies and animations.

that's like asking if a pen or keyboard lead to bloat. depends on who's using them.

More like if AI leads to spam or if guns kill people.

The latter one is harder if you only have a knife instead of an assault rifle.

No it’s more like, does vscode lead to better code than jetbrains? Figma doesn’t really provide meaningful constraints on a design that would let you identify it as Figma sourced, much as you won’t be able to tell whether a site was written in a particular IDE.

You seem to have a fundamental misunderstanding of what Figma is. Your question would be better answered if you took some time to look at figma, rather than looking at the designs people create with figma.

So tell me why the UX in the web gets worse if all these tools and framework make the DX better?

On mobile I have a limited data plan and the speed isn't always the best and on many pages I have to wait because beside the ads I have to download 3, 5, 10 or even more MB of data just to get pages where button, links and headline are undistinguishable because of recent design decisions.

Seems to me these tools are worthless in the end, if you are a user. After bootstrap it went pretty much downhill.

It's good with SVGs, themes, grouping elements into reusable components from your design system, and doing an art board per screen together so you can get an idea of your workflow through the app.

Not great at animations, not great at fully exploding all of the app state. Overall pretty good middle ground for designers and devs to interact.

If a designer uses ‘unnecessary’ transparencies and animations just because a design tool makes those things easy, that is not a problem with the design tool.

If a tool makes something bad easy it is partially responsible.

It’s just a system for animating the transitions between flat designs and adding scroll areas so you can preview an estimation of a design on mobile and web.

Doesn’t even support more advanced prototyping things like inputs and dynamic changes.

Not a site builder

Most large sites you see are made "with Figma". Designers use Figma for mocks and hand it off to web developers to implement.

You can safely assume everything that comes out of Microsoft is designed with Figma.

As mentioned, Figma is the de facto standard for UX design. Probably six or seven out of ten websites, apps, and desktop applications were designed on Figma, if they're relatively new. But Figma doesn't make sites, it's just a tool for designing them.

If you sign up for Figma, you can quickly get a sense of what it does. Some features are behind a paywall, but mostly things related to collaborating or managing large teams and design systems.

There are also approximately 1 billion Figma tutorial videos on Youtube that would show you the interface.