So with this future of vibe coded tools , how to choose which one to use?

A lot of what makes Canva stand out comes from its IP coupled to their ecosystem/product (templates, assets and stock photography), its otherwise a pretty simple tool with basic functionality (but with good UX) compared with more professional software like photoshop or illustrator, or Figma. I'm sure you can built an open source equivalent in terms of software, but I don't think it's really possible for open source to produce a true replacement or alternative.

THAT ASIDE, it might be worth focusing on UX. This looks vibe coded, maybe it isn't.

- The UI is broken in a few places (the tools text in the shapes menu)

- Consider prioritising more important tools based on available space in the ui, the header is a bit cluttered.

- Some of the tool menus are awkward to use, like in Canva those are in a side bar and when they open the have panels that don't disappear when their parent looses focus. Probably worth making sure you're not using their exact icons as well as these look pretty similar.

- Your add page button is creating an awkward scroll which you could probably limit by exposing add page in a way that didn't do that. Maybe remove the add page button below the canvas, as you already have an add page button in the bottom left, you should have more vertical space for the design as a result.

- You've got several different export sharing options in the header side by side. Might be worth collapsing that into a menu to minimise clutter. Both tools like canva and more professional tools layout their UIs like this. By all means do don't it just because they are, but there is some rational here why they would.

- There are two places in the header that talk about the save state on the left and the right (one saying saved, the other saying saved in the browser). Consider having consolidating that.

- do you really want to place the copy "Sign up to keep it forever" next to the sign up button? do you have any reason this is likely to stand out from the rest of the UI features there? I reckon if not get rid of it. Or if it's that important get rid of anything competiting for its attention which right now is a lot of things.

- you have a ellipses for a menu with a ton of options, in most software this is aligned to the left. If you've removed other things frmo the the head it may make sense to break that up in submenus so those pieces of functionality is more discoverable.

- Your commment functionality requires sign up to use, keeping it there may help lead to signs ups, but if you're designing this as an open source tool, maybe you're less interested in growth hacking, it might make sense to remove it from the header as well when the user isn't signed in (at the same time keeping it there signals to people weighing up your product that that feature exists.

- you have 2 layers of headers, is it worth utilising horitonzal space for some of your buttons and put them in the right hand side?

Hopefully you can feed the above back into your agent on a loop lol.