Let me educate you quickly about my tennis life.
As you say, I'm a 4.0B. Last year, I was a 3.5. I was bumped up for obvious reasons: Strong play at 3.5, including 6-0 at senior 3.5 nationals and 13-0 in 3.5 adult regular season and districts. So no, I didn't have mostly losses at 3.5.
This first year at 4.0 has been rougher, but that's how it goes when you get bumped up. I am working on my game, and things are getting better. I win some, but I need to improve my groundstrokes and volleys.
The reason I feel the need to hammer you is that you pull all kinds of stuff out of your backside. I have played against a large number of 4.0 women. You, apparently, know *one* 4.0 woman. Yet you claim you know that a 4.0 woman with a weak serve isn't a real 4.0 woman, or is pathetic, or is an octogenarian.
I am here to tell you that you are wrong about that.
Honestly, you probably should stick to what you know. You are a 3.0C. Perhaps you are really more like a 3.5. That's fine, nothing wrong with that.
But when you then pop off about what 4.0s and 4.5s can do . . . Sorry, I just don't think you have any idea based on personal experience in competitive matches.
-- Random Error Generator, Version 4.0
-- Master Moonballer