Let's not rewrite history just because of what's currently happening with him.
If 2018-2021 Rashford was playing for another club, everyone on here would've considered him 100 million talent and a dream signing, much like the likes of Williams, Kvaratskhelia, Wirtz, etc. are now.
Especially in Ole's two full seasons. He was in his early 20s and getting 25-30+ G/A in the Premier League and Champions League, whilst playing for just a top 4 contender side, whilst being a young English inside forward with lightning top speeds and acceleration, great power, great ball striking, great ball carrying ability, having that x factor, great big game record, etc. He also had a lot of flair to his game and wasn't just a player that maximized his game for efficiency but was otherwise arguably not that exciting to watch play.
If we compare him to Sancho, he's comfortably a more valuable profile and a miles better player, especially in those years I mentioned, and Sancho himself was considered a 100m+ player because he was a flat track bully in the Bundesliga.
If he was playing for a selling club or a mid-table PL team, and not a top 3 club in the world, he would've been held in the same regard during those years as most of the 100 million talents today. But United fans often don't realize what kind of players they have on their hands. Rashford in his best seasons at United, Pogba, Maguire under Ole, Bruno under Ole, Shaw in those seasons where he stayed fit and United had a half-decent team, these were some of the best players in their respective positions on the whole planet, but United fans love to abuse their best players for some reason.