I would be grateful if someone could help me with identifying this cacti I bought. I did some research and concluded it could be Pilosocereus chrysostele. But I am not really sure as there are some similar cacti out there.
Yes, Your cactus is a Pilosocereus chrysostele; There are many cacti which are similar in appearance, and P. chrysostele is a popular variety: They're robust and attractive. Maybe carefully check how yours was set in the container, there should be some coarse gravel in the bottom, & a hole(s) in the bottom for drainage. Nice healthy looking cactus!