I ported an Angular Universal app over to Svelte after one of the Angular major upgrades failed due to an Angular Universal bug that been around for years. Working with Svelte has been been great. I also like custom architecture since large apps will need custom architecture anyways. After porting the app over, it was easier to refactor the code without a heavy framework like Angular getting in the way.
I also maintain a large app in SolidJS. I like SolidJS even more than Svelte, especially for large projects but also for small projects.
Svelte has some disadvantages with tooling & some issues with Typescript integration. SolidJS allows more function decomposition & general flexibility in creating smaller more focused components, since the jsx/tsx components are plain old javascript functions. In addition, SolidJS javascript output is smaller than Svelte when the app hits a fairly low level of complexity. The engineering of SolidJS is more accessible than Svelte, so it's easier to understand what is going on.
I also maintain a large app in SolidJS. I like SolidJS even more than Svelte, especially for large projects but also for small projects.
Svelte has some disadvantages with tooling & some issues with Typescript integration. SolidJS allows more function decomposition & general flexibility in creating smaller more focused components, since the jsx/tsx components are plain old javascript functions. In addition, SolidJS javascript output is smaller than Svelte when the app hits a fairly low level of complexity. The engineering of SolidJS is more accessible than Svelte, so it's easier to understand what is going on.