Can anyone recommend a mobile phone with the following features?
* no Google services (e.g. by running an alternative rom)
* not too expensive (it's for children)
* not too bulky
* gets updates
* runs Signal
* at least 4G
* not produced by Google => no Pixel devices

EDIT: * no iPhone

I still own a Samsung A3 2017 which would fit those requirements. Unfortunately, I did not manage to flash it with an alternative rom.

#PurchaseRecommendation

@a32 I used to enjoy the Huawei / Honor phones before they were blocked from using Google Services, so if you don't want Google, that could be an option.
Cheap, good quality, not too much crapware from what I remember