Well I can't ride it, it's so slow, it won't go up a tiny hill the pedals are underneath my seat, the handlebars are too high and the only seat small enough to enable me to reach the floor is so painful
I could cry
Go into the settings and in one of the three things, say rocket, set everything to the maximum and try again.
Also, accept going a bit slower to begin with, certainly do not expect big beefy rear hub cadence sensor speeds, and make sure you are are spinning the pedals fast enough. Minimum 60 rpm, 70 is better.
Use the gears effectively to keep your effort constant when the gradient changes. It will not bail you out with extra oomph.
Apologies if you have already done all of this.
Don't cry too much, Fazua bikes may be a smallish niche but they have no real competition in it, so likely if it comes to it that there is a buyer out there.
You are right that it is not particularly powerful, but that's by design, their intent is to suit riders who have lost their top edge, but do not need assistance on the level unless a head wind. That's why they specifically combine zero resistance when not assisting, light weight, and a torquey motor that drives through the gears.
The ideal rider is a club rider who can't keep up on the hills anymore, but is otherwise fine in a group ride. Alternatively someone recovering from illness or lack of fitness who wants to do quite a lot of the work, quite a lot of the time.
They do not suit pannier laden touring, heavy shopping trips or riders who need a helping hand all the time.
Saddle, bars, stem ought to offer enough possible range to find a riding position if you can come to terms with the assistance level.
Your ideal bike may be either what you had before, or a top end mid drive with at least 70Nm torque, and the biggest battery you can get. That will get you all the help you need, as long as you almost never want to go above 25km/h.
Good luck!
Edit:
I forgot to mention the bit advantage other mid drive torque sensor bikes have: it is simple: in the highest level, they contribute 400% typically of the riders effort. Your Fazua is me ch, much lower. I would have to go back to the g dph, but I think not a lot more than 100%. So day and night.