Are these costs still normal even in these times?

If you have no idea about construction, then the offers are correspondingly bad and in the end, money has to be spent on changes. You pay a learning fee, I know from experience. And it is much more stressful to have to do everything yourself. It takes a lot of time to always be able to discuss everything on the construction site.

In general, I trust an architect to make a proper and complete tender, which makes the offers better and cheaper.

Doing the tenders yourself because the architect is too expensive? You probably also draft all the contracts yourself because notaries and lawyers are overpaid anyway? Well, no risk no fun

Because it is inhabited and will probably remain inhabited during the construction phase: