A big and highly sought-after striker like Victor Osimhen would not just be considering playing in the CL, he will want to join a team that can actually compete for it and prolly win it, Napoli might not guarantee a player CL football every season, but at least every now and then they find themselves in the competition, so Osimhen already knows what it is like to play in the CL, winning it should be next up on his mind.
Having said that, i would love to see Victor in the EPL, i know Chelsea seems like the only EPL team interested in him right now, and they are a team in transition, so winning trophies might take sometime if Osimhen decides to join them. We can only continue to debate on his future, but we'd find out what he will do in the summer.
It's just a matter of time, but I believe Osimehn will soon join a big team, one that will give him a better chance of winning the Champions League trophy with them. As you mentioned, he has only been linked with Chelsea so far, and they appear to be more interested in him than any other team in the English Premier League. I also read that after Mbappe decides to leave PSG, the club is looking to sign Osimehn as a replacement.
I'm not sure how well PSG can win the Champions League trophy with their current players, but Osimehn's arrival isn't a good enough sign for them to do so. They've had other big players play for them and failed to win, so even with Osimehn, I doubt they'll win. PSG is a Ligue 1 team that is always guaranteed a spot in the Champions League each season, but winning it has been their biggest disappointment.