Is buying property now sensible? Experiences?

That can only be satire... 9,500 net per month, no children, and wonders if he can finance 500,000 EUR?

If you put aside 5,000 EUR every month, you have about what we currently "have to get by on" with 2 children.
And even then, there is still some left over.

Also keep in mind that it takes time before the construction actually begins. You don't just do the floor plan, construction company, and financing casually, and it is also recommended to have sufficient calm during this process. Therefore, I would start now so that everything is ready for signing by summer. However, for 355k, you will hardly get a house unless you put in a lot of your own work. With your income, much more should be possible. In my opinion, your very first appointment should be with the bank to clarify the financing framework. Then, take a critical stock of what you want, what you can do without, and what you might be able to do later.

For 355k, however, you will hardly get a house unless you put in a lot of your own work.

With a well-known large general contractor, you can get a 152m² turnkey house without additional construction costs for 320,000 EUR. Price for the Hannover region.

So. It's possible.

In Lower Saxony, it is naturally cheaper from my own experience than in Bavaria. However, the price still seems very low to me. Does that already include electric shutters, underfloor heating, and painter/flooring? You can easily add that to the 320k, and then in the end you will still come to around 3k per m2 including incidental construction costs.

With a well-known major general contractor, you get a 152m² house turnkey without additional construction costs for 320,000 EUR. Price for the Hannover region. So. That's doable.

Anyone currently paying a warm rent of 2500 EUR/month for an apartment will probably find it very difficult to commit to a house with construction costs of 2100 EUR/m². I see bigger desires in terms of space and equipment. Who lowers their standards without necessity?

up to an amount X (=> house financing)

If I understood that correctly, I would advise caution here. You should not commit to the financier now for two or three years, that can become very expensive. On the other hand, it was already mentioned that you can repay the loan quickly. If you want to.