Front-end development is a core component of any modern application development stack. As a bridge between the user and your software, it constructs an interface that gives a digital representation of the system they are interacting with. There are two types of front-end development used today- UI/UX design and coding.
The main thing in your projects is value for your customers. Then ask yourself. Is cool react-angular-typescript-frontend really need for your customers? Or they can use your project build on top of WordPress with server-side rendering and thats ok for them?
Dont forget that there are a lot of pitfalls with SEO when you have frontend as single-page-application (SPA). You need to add server-side rendering for it, configure your server and so on.
If your project already brings money then you can optimise it, add some cool frontend and so on. If not then just build it in comfort and fast way.
No, you don't need front-end development to build/design the UI/UX of your software. However, it can be helpful to have at least a basic understanding of front-end development concepts in order to create a well-rounded user experience.
Nowadays, if you can build a solid backend, you can use no-code tools for your frontend, with very little experience.
From experience working as a UX/UI Designer, our job is to take the business requirements from the business department (usually in the form of a BRD or a UX workshop) and we translate it into design files, journey maps, prototypes, style sheet. After that we have a meeting with the front and backend developer and handoff the design files to be developed( UX/UI is like the blueprints and developers are the construction company that turn it into reality)