Evaluation of offer (5 windows and a balcony door including removal and installation)

Hello everyone,
I have received an offer for the installation of new windows (including removal of the old windows and disposal). Since this is my first time doing this, I would like your assessment on whether this is a good price (location Ruhr area).
Offer price 5,100 euros gross
Included according to the offer
Veka Softline 76 AD
2 windows: single-leaf tilt-and-turn window measuring 1210 x 1460 mm, double insulating glass Ug-1.1, white (347 € net)
1 window: single-leaf tilt-and-turn window measuring 1215 x 1450 mm, double insulating glass Ug-1.1, frosted glass, white (391 € net)
1 window: double-leaf tilt-and-turn/turn window with fixed mullion measuring 1820 x 1460 mm, double insulating glass Ug-1.1, white (602 € net)
1 window: double-leaf tilt-and-turn/turn window with fixed mullion measuring 1720 x 1460 mm, double insulating glass Ug-1.1, white (582 € net)
1 balcony door: single-leaf tilt-and-turn door measuring 790 x 1970 mm, double insulating glass Ug-1.1, white (343 € net)
Dismantling, disposal, and installation of 6 windows including foaming, internal finishing, external sealing; painting work done separately by a painter (1,710 € net)

Thanks to you all!

Get identical offers from two other companies, then you will have current reference prices and can classify them.

including foaming, internal finishing, external sealing

I would ask more precisely how exactly it is carried out

Compared to my recently ordered Softline 82 MD (colored outside), quite expensive.

VEKA Sofltine 76 AD

Why only AD?

I really don't know anything about that. I have seen the MD in online configurations. The windows are generally much cheaper there. But I don't want to order windows online myself because I simply don't know anything about it and then I can't find anyone to install them. The companies all want to order the materials themselves. I have now contacted 3 companies with the data from the first offer to see if they can give me an approximate quote without an on-site appointment. The costs for installation seem extremely expensive to me.