The central striker doesn't necessarily have to be of a high calibre technically (first touch/ball control) to excel in a team that wants to dominate the ball. As long as his first touch is functional, then the chances of him being successful are good, as long as he has other strong attributes that will improve the team as a collective. And from what we've seen of Osimhen, he presses high, has pace/power, aerially very strong and can finish chances at a good rate. He looks tailor made for a team that wants to pin the opponent in their own half and his off the ball pressing would potentially help in defending from the front. And his pace, power and athleticism, along with his strong aerial game where 30 % of his goals have come from headers, would also potentially open up a variety of possibilities on the ball. A right back with the ability to combine, connect and deliver crosses, would also make signing Osimhen a logical choice.
A possession team that looks to dominate the ball with the aim of playing vertical passes at every possible opportunity, must have technically strong players in the first phase of the build up. And those players, starting with the GK and then CBs, deeper mids and fullbacks need to be of a high technical level or else the vertical positional play principles will fail to take off. Bruno Fernandes isn't to blame for that and neither are the rest of the final third players. I would say the lack of effective build up play from the back causes problems for the final third players. And fixing the issues at the back will open up even more possibilities upfront.