> I have had much harder time fixing badly written Angular projects (all versions) than such written in React.

What is the inherent issue with Angular? Data fetching is done by services, components use them, components' presentation logic is in html/scss files. If a component is particularly simple/low level, it takes data as input which can passed by the higher level component with help of services. I have found this to be very easy to reason about as long as the structure keeps in mind what each bit's role is in the big picture. Separation while keeping logically connected things close e.g. the component and its html/scss are usually kept together.