Milan Aleksić was a part of FK Partizan academy. Partizan is a club that has been producing top talents for years and their academy has been the highest rated academy in Serbia for years. He went with their first-team pre-season and was excellent, but for some reason he wasn't under pro contract at the time and Radnički Kragujevac stole him from Partizan. Radnički had a terrible start of the season, as they lost first 6 games, with Aleksić only making one appearance of the bench. They then won the next game and lost the game after that with Aleksić not featuring at all. They looked like relegations certs. Their coach got sacked and the new coach that came in started giving youth players lot more chances and he let them play with freedom. They made a good run in which Aleksic was coming off the bench and then around February he completely exploded. They went on a 8 game unbeated streak(drew first two and won 6 in a row after that) and Aleksic was one of their best players. They ended up securing a UEFA Conference League qualifying spot, which is the first time they reached a European competition in the last 54 years. This season, he was probably the only good player in those two qualifying games, and you've already seen the two goals he's scored as the video has already been shared here.
He now got a call up for our senior national team for the Nations League A games against Spain and Denmark, so if you have time to watch those games you might get a chance to see him play (if he gets a chance to play that is).
Not sure what formation Sunderland plays, so not sure where he'll slot in, but his best position is the number 8 role. He can play as a 10 too, and even as a defensive midfielder, although I think his defensive attributes aren't good enough for him to be the only defensive midfielder, but it could work if it was in a "double pivot". Without a shadow of doubt, his best attribute is his passing. One of the most naturaly gifted passers I've seen. His shooting and ball carrying is excellent too. He's a very confident, hard-working player. That being said, Serbian league is much slower paced than the Championship, and he'll most likely need some time to get up to speed. I hope that you'll be patient with him in regards to that. I'll try to watch as much games Sunderland games as possible now, as I do with all Serbian players abroad and I hope you'll do well.
I probably forgot some stuff I wanted to say, but this it it for now. If you have any questions you'd think I could answer, feel free to ask.