Recommended climate station (indoor)

Dear forum community,

I currently have some cheap hygrometers/thermometers from eBay to monitor the indoor climate in the house, and although they are quite amusing, I'm sure they are not particularly accurate.
Which indoor climate station can you recommend?
I am setting a price limit of 100 EUR, but it should definitely have data logging with app access.
It would also be cool if it runs on "normal" batteries, so no special button cells or even integrated rechargeable batteries.
Expandability with sensors for different rooms would also be good.
Experience reports regarding battery life are also very welcome.

Thanks and best regards
Tolentino

Indoor/outdoor display, no app/data log, just our help with cross-ventilation, about €10 at the yellow discount store

Help me out, which one is the yellow discounter? (Brutto ohne MwSt mit und ohne Hund?)

Good question. I have even been wondering for some time whether there might be a possibility to use the obsolete ERR control elements, respectively their space and power connection. Hygrometer/thermometer flush-mounted, in every room, with power connection, that would be something! Unfortunately, I don’t have the slightest bit of automation in the house.

to use obsolete ERR controls, respectively their space and power connection.

Hygrometer/thermometer flush-mounted, in every room, with power connection, that would be something! Unfortunately, I don't have the slightest automation in the house.

Uh, that would also be an interesting product for the next winter, after the construction moisture has been aired out here.

Regarding the topic, I have been considering the Netatmo products.

we have that from Lidl, there is also a symbol airing/not airing/never air