This is a really difficult topic that has led many astray and away from the right path. The correct belief is that we neither have full control nor are we totally powerless. Also it's recommended to not think over it too much as again it's gonna led you astray and just keeping the right belief is enough for keeping your faith healthy.
I'm sure you are interested in references but I can't provide any authentic ones as I'm talking this through knowledge gained from Sufi books which hardly mention references. The best known book "Kashful Mahjoob, Unveiling the Veiled" by "Hazrat Data Ganj Baksh Ali Hajveri (R.A)" details this topic. According to him, during the old times when this fitna surfaced Hazrat Hasan Basri (R.A) asked details regarding this from Imam Hasan (R.A) and the summary of his reply is that,
"Faith lies between total fatalism (meaning no control) and total freedom". An example of this is a farmer who sows seeds and reaps what crops grow from it. While he is in control of his actions apparently, he is certainly not in control of how the plant will grow out of that seed. This is Allah SWT doing. Similarly the strength to sow and reap was also given to him by Allah SWT, so he isn't in full control, nor is he totally powerless.
Imam Hasan R.A writes that "In the actions, Allah SWT has made mankind in control, He is the real one in control." Since nothing happens without his will. He also writes "Thus, Allah SWT doesn't stop anyone if he decides to disobey or obey him. However He can if He wills, stop a person from doing a sin as a token of his mercy. But this doesn't mean that if He doesn't stop a person from doing sins, He was the one who forced him to do sins. Allah SWT has given the ability to mankind to do good or evil"
He also mentions clearly that
"Not believing that everything (good/bad) is from Allah SWT leads to or is infact "kufr". And whoever attributes the doing of his sins towards Allah SWT is Fasiq/Fajir i.e. evil-doer".
If you can live without authentic references to Hadiths like Bukhari and Muslim, then try reading the book I mentioned.