First, since you can't see me, my facial expression, or hear my tone, please understand their is no animosity here :)
Good to hear, I think once you start learning the flow of FG you will learn new things quickly.
Always nice to have have another application/software/IT professional on the boards, their are dozens of us, many with many decades of experience. But, understand, FG is not a game. And software games often have a very different development and support lifecycle than collaboration applications that use a database do (which a VTT is). Even most game engines are obsolete and replaced with new ones in a fraction of the lifespan of FG.
As for an overhaul of the UI, as others have said. It's known and it's desired. But you also have to understand that this is a niche application that doesn't make millions of dollars. It doesn't have a dozen developers working on it full time (or even part-time). Think of it this way, if you had written and released Doom (1993) and you had to maintain that game, adding new capabilities, yet constantly maintaining backward compatibility, not only to all the DLC you create, but to community created DLC as well for 20+ years, and do it with 1-2 developers. Would Doom 2018 still have remnants of Doom 1993? Of course :)
(Now, it's not impossible, Smiteworks is in the process of doing this, FGU, and they have invested (from what they say) over 10k man hours to FGU. And they have invested much of the profits derived from their licensing of 5E into hiring a developer who works full time on FGU.)
Ideally, FG wouldn't be hard to learn. But again, it depends on the person. I think I DM'd my first session after 2-3 hours setting up my campaign and the learning curve for the basics was minimal. Maybe it's because I'm old enough I get how older interfaces work :)
FG has never been, and the developers are quite clear that they do not intend, a full fledged character builder. It's a VTT. It's not advertised as a character builder, even though many of us use it that way without complaint. Why you paid/bought what you did, is only a question you can answer :0 Many people on here have all three like you do. And many are like me, we've only bought 5E products in FG. I have no need for a physical book, nor does DDB give me anything of value (IMO) compared to FG. Heck, many people on the forums here also pay for other VTTs as well, using each for what they feel is strongest. Me, I just find one tool that does the things that are important to me and make do with the things it doesn't do strongest.
I think Talyn has pointed you to the right thread. But you have to understand the business and resource realities of FG. It does not have a dozen developers who can break out the different parts and work uninterrupted.
Also, SW it exceptional at supporting the current product (weekly DLC updates), plus roughly quarterly new functionality.
Sure, their is a huge opportunity for improvements. And discussing them is great. Also, check out the wishlist;
https://fg2app.idea.informer.com for some of the idea that have already been suggested, discussed and voted on. Do note that the default filter is based on votes, so the really old stuff shows up first. That and a lot of ideas there have already been incorporated but aren't marked closed.
Not sure where the thread is, but their is a long one on the UI, talking about tabbed windows and all sorts of stuff. You might enjoy reading and even re-awakening that thread.