What is the depreciation value of an 11-year-old built-in kitchen?

It is not a new owner, it is the old owner who now wants to move back in and who, if I understand correctly, once forced mom to buy the kitchen.
Furthermore, she apparently harassed mom a lot during the rental period. But she would probably like to have the kitchen.

The obviously not very high-quality kitchen is worth almost nothing after 11 years. Normally, you can be glad if the person taking over the house/apartment also takes over the kitchen without any issues.

But here it’s a bit different.
You can see what the owner would give you since she would like the kitchen back.
If that’s too little for you, you can either swallow the bitter pill and just have no further work with it. That would be the comfortable option.
In any case, make sure that the kitchen remains as agreed upon mutually. You don’t want the owner to later decide she doesn’t like the kitchen after all and make you cover the disposal costs. If she has been such a nuisance in recent years, I would get that fixed in writing.

Of course, you can also get back at her and sell the kitchen for little (although I fear you won’t get anything) or give it away (for pickup). The owner can’t do anything against that, since the kitchen belongs to mom. And the owner won’t get her kitchen.
If that’s worth it to you...

I would try to get out of this with as little work on my part as possible. Maybe the owner will pay you a recognition amount. If not, I would personally let her have it at no cost before having work with it. Mom definitely doesn’t want to keep it.
Maybe the owner will then accommodate you in another matter.

You understood everything correctly and that is exactly how we will proceed, thank you!

It must be said that the kitchen is still in great condition, the stove/oven has hardly ever been used.

Is the notice of termination for personal use even permissible?
Where has the owner lived so far?
Google a bit and educate yourself on in which cases a notice of termination for personal use is excluded, it's not that uncommon. For example, if she has other adequate property or similar, there are several possibilities.
If permissible, I would tell the lady: 2000€ or I need a very, very long time to find a new apartment, money for rent is also becoming very, very tight right now.
I really love things like this, landlord forces a shitty kitchen to be forcibly replaced and then harasses over years.
Now you hold the upper hand, don’t let the lady fool you.

Thank you for your statement! I believe my mom has already been to the lawyer, but I can gladly ask her again.

Hello,

the post is already 2-3 weeks old and maybe everything has been settled by now, but I would name a price to the old and new owner (flat rate 1500,- negotiable, if she negotiates the kitchen stays for 1000 and that's that, zero stress for you) for that she will never ever get a new kitchen so quickly.

and if not, nice photos, a fruit basket, a few flowers and off to classifieds with it, there is always, really always someone.

best regards Claudia

Hello Marvin, the condition of the kitchen can still be great, especially if mom has been careful with it. Nonsense that it can no longer be worth anything. Insurers calculate like this: depreciation in the first year 24%, then 2.5% each year. On top of that, you can add 50% at the end, which is generally also recognized by courts if the buyer complains afterward. Basically: as seen, so bought, and nobody has to buy if they don’t like it. So the kitchen can definitely still be worth 70% of the new value.