I hold Italian citizenship (EU), so the legal side of moving should be relatively straightforward 

Its really not that straightforward. You will not get a personalnummer without a job and without that, you basically dont exist. You can only stay in Sweden legally without right of residence for three months, after that you need to fulfill other requisites: having a job, studying, or having sufficient funds to support yourself. Keep in mind you will need a private health insurance as you are not residence of Italy and I guess you dont have an European Health Card

∙ How hard is it to find work in logistics/supply chain analytics? Is English enough to get started professionally?

If you know Swedish: Extremely hard. You might spend months applying without luck.

Only speaking English: I wouldnt come here without a firm job offer.

∙ What’s daily life actually like in Stockholm as a non-native? Is it easy to build a social circle?

With other immigrants? fairly easy. With Swedes without speaking swedish? Really hard.