@ilkleymoorbartat
I'm sorry you're disappointed, it's horrible when things don't turn out how you thought they would.
I like the actual carpet well enough, I just think it's the wrong tape, but that's a massive hassle & not insignificant cost to have replaced.
How much expense/upheaval are you up for?
If it were me, I'd be going for minimal of each as it looks like you've already had a lot of both!
I'd paint the bannister tops to match the posts and spindles, I like natural wood, but to me it is a bit orange & doesn't go with the rest. Just be careful with the paint!!!
Then try a big picture/print on the wall straight ahead from the bottom of the stairs. One you love that's not neutral!!
If YOU like houseplants one in the stair turn corner and one trailing on the window sill. If, like me, you're not keen on plants then you could try an unusual, colourful, object.
Not the red tape as in one of the photos. Painting the stairs (again) would help, but it's a big hassle and I think you can fix this without the upheaval & too much expense.
Let us know how you get on!!