aircon that only heats?

So I guess a lot of us are shivering in their cold homes.
I happen to learn to have to use the aircon to heat my room.
To my astonishment when it reaches the desired temperature it suddenly starts to blow cool air!
Well it makes sense, it is an air conditioner at least, isn't it!

So I wonder are there types that have a heating only setting?
It would work like this:
- you set the desired temperature
- when the temperature is reached it just goes idle
- if the temperature drops below the desired temperature it starts heating again
* optional: maybe a temperate range can be set so that after going to idle it will only start heating again if the temperature drops x°C below the desired temperature

Do appliances with a function like this exist? What keyword would I have to watch out for?

I don’t know exactly what kind you have, but does it have a selection among:
Automatic 自動, cool 冷房, heat 暖房, (maybe in addition: dehumidify除湿, air cleaning 空気清浄), etc.?

If yes, and if the air-con does what you describe, I suspect it is set to “automatic.”
Can you switch it over to heating （暖房）?
Then all it does is blow warm air until the room air temp reaches the pre-selected temperature, and just stops blowing when the temp you want is reached.

Sounds like you have it on auto. Not heat.

No actually I set it to heating. But maybe Daikin is just...
I now moved to another apartment and there is an older Panasonic installed, which behaves totally different and like I would expect.

then you have it set to the highest heat setting maybe?

if you have it on the highest setting, when it reaches or surpasses the temp, it will attempt to cool for a few moments to hit the desired temp setting.

if this scenario is what it happening to you? then set the temp 2 degrees lower than the maximum. should prevent the system from attempting to cool.