Your opinion requested / unmarried financing

Hello everyone,
I have been thinking about this for days and I need your tips/opinions, please.

It concerns an upcoming land purchase and the construction of a single-family house. Briefly to the facts:

-Couple, unmarried
-I bring equity: approx. 150K
-She unfortunately has no equity
-I am the borrower because she is currently on parental leave but plans to return to work in the foreseeable future.

I want to make it as fair as possible but also protect myself so I don’t have an unpleasant surprise.
A possible scenario for me:

I am the borrower, am listed in the land register, and pay the loan. She, upon resuming work, could for example pay the monthly additional costs or later be entered into the land register. Or by notarized agreement what happens with the house in case of separation etc. and that each gets back their paid share of the loan (2nd option).

Marriage is currently not an option.
How would you do it? Have I perhaps overlooked something?

Thanks for your help
Piotr

Registering her in the land register is equivalent to a gift. Since you are not married, gift tax is due on everything over €20k. If only you service the loan, it is okay if only you are listed in the land register. Before everyone starts complaining again about providing for the woman: it is better to conclude a contract that secures the girlfriend accordingly in case of separation. There are many possibilities here.

She should definitely be registered in the land register for her protection. After all, it is because she stays with the child that you are able to work. Therefore, she should also have an equal share of the income and also the house / the repayment. That you contribute 150k more equity can be recorded in a private contract, which does not even have to be notarized. However, he can also advise you in this regard.

Registering her in the land register is equivalent to a gift.
Since you are not married, gift tax is due on everything over €20,000.
If only you are servicing the loan, it is okay if only you are listed in the land register.
Before everyone starts yelling again regarding the provision for the woman: better to conclude a contract that secures the girlfriend appropriately in case of separation. There are many possibilities here.

Have you had personal experience with this?
Can you send me a private message?

I am married. However, my wife is not listed in the land register because even the exemption allowance for married couples would not be sufficient. Therefore, everything is regulated by a marriage contract and a will. For us, it is also somewhat simpler because we have no children. You could, for example, make a contract that your girlfriend receives x€ additionally over x years. Or x% upon sale... This is very individual. It is advisable to seek help from a tax advisor/lawyer/notary.

I am married. However, my wife is not listed in the land register because even the allowance for married couples would not be sufficient. Therefore, everything is regulated by marriage contract and will. It is a bit simpler for us since we have no children.
For example, you could make a contract that your girlfriend receives x€ over x years additionally. Or x% upon sale...
This is very individual. It makes sense to seek help from a tax advisor/lawyer/notary.

I have to provide the data for the draft purchase agreement and will not be able to clarify this in advance. Everything has been very tight in terms of time. But this should still be able to be added/secured contractually afterwards, or what do you think?
I am really grateful for this forum! Thanks for the help.