Painting over old latex paint with latex paint

Fine multitool with the putty scraper attachment would be worth a try.

Could really be useful, but 250€ for a try...

...on the other hand, I don’t know how else we could complete the work promptly and mentally healthy.

As already mentioned, I find the "Fein multitool with the scraper attachment" exciting.

Before I buy this not exactly cheap tool, I would like to ask about an alternative...

For example, my painter mentioned an electric (battery-powered?) "scraper with a blade" that plasterers use... According to the description, the blade is supposed to be relatively wide. Who knows this tool and could provide a link?

Links are not allowed here. Google [Elektrospachtel] or [Elektroschaber], then you will get devices from China to Metabo. But if you do something yourself more often, then the Fein multitool is unbeatable useful and really good quality. This winter I removed an entire ship's deck from its glued covering, scraped off the adhesive residues, then sanded everything, all with just this one tool, which neither gets hot nor is too heavy in the hand. Advertisement block Fein ends here.

I would also prefer to scrape a ship's deck ;)

Let's see what I can organize tomorrow.

Thank you for your valuable thoughts!