"I still have doubts."
Translation:Wciąż mam wątpliwości.
Can it be: Jeszcze mam wątpliwości? And is 'still' really a good word for 'wciąż'? What about 'constantly' or 'continuously'?
Yes, "still" is a good word for "wciąż" and it fits much better in this question than "constantly/continuously". The more accurate translation for "contantly/continuosly" would be "stale".
A little one maybe. „Wciąż” is still in regards of time. As in still meaning now or not yet. „Jeszcze” is more universal. Can't recall at the moment a situation, where you can use „wciąż”, but not „jeszcze”.
It seems to me slightly different, but yes, acceptable. Added.
"Jeszcze", for me, sounds a bit like "OK, some of my doubts are gone but I have new ones", while "Wciąż" more like "Well, some of my doubts are not gone yet". But this is obviously a subjective opinion.