Thank for the answers. And just to reply to some:

- I do not need faster hardware, but as others I do not wan't to pay 250 for outdated hardware (especially in terms of display readability)
- used ones are not really available as the market is quite small
- spare battery is a joke as there is not possibility to buy one


As for the solution (maybe only temporarily):

I ordered a Ubuntu Phone (Aquaris e 4.5) for 130 (so half the price of the Jolla).