There are tool tips. Any button you over over gives you a small description on what it is.

I fully agree, but that's the best thing about KiCad, it's fully open source. If you don't like the way anything looks you're free to change it! There is going to be some significant changes in KiCad 9 as well that may make things easier. We will just have to wait and see

It's just the industry standard. Altium (most popular EDA software) is similar. KiCad shares lots of UI from them. There's always other tools like Flux that are totally different

This screams a ME doing a EEs job

Most solder paste already has the ideal flux ratios, you shouldn't need to add more unless you're reworking it. Too much flux will cause the solder to become runny

Also, if you're soldering any SMD parts by hand (not hot air) there's no such thing as too much flux!