Hi, yes you can do this without any framework, especially if you know that you will only be using modern browsers. Indeed, you could use the new HTML module features which can offer some of the features only previously available in web frameworks.
Of course, doing it all without a framework will require some additional web development skills.
Remember that the purpose of uibuilder is to create a "glue" between Node-RED and your front-end code. It manages the communications for you and helps with serving up front-end libraries. The idea is to make it really easy to have a data-driven web user interface.
So you can use any or no front-end library.
I would say though that VueJS is about the easiest of the mainstream frameworks. If you want to get going quickly and don't have any other specific experience, that would probably my first choice.
Svelte is a really nice framework however, it requires a build step which is another thing that you have to learn to work with. Not especially hard and once you've got it working, it is nice. But a little extra overhead if you want to get going quickly.
While I'm not great web programming expert, personally I would steer clear of all of the other frameworks as they seem to me to be far too complex. Had another play with REACT the other day and I was horrified at how much more complex it is than VueJS. I'm sure they have their own strengths though and if you are familiar with them, uibuilder won't really care
One thing I do recommend though, for serious work, don't bother with uibuilder's editor. That is great for quick changes and that's how I use it. For actual development of a UI, I use VScode's remote editor extension which is much nicer to work with.