Might be a good idea to demonstrate this trend with some type of data, because I'm here to tell you it's another falsehood. You tend to spit those out left and right.
There were no later round receivers that had more success than Justin Jefferson, Ceedee Lamb, Jerry Jeudy, Tee Higgins, Henry Ruggs, Chase Claypool, Brandon Aiyuk, Michael Pittman, Laviska Shenault, Jalen Raegor, and K.J. Hamler from the 2020 draft. They were all top 50 picks and 6 came off the board in the 1st round. Furthermore, Day 2 has always been a good place to draft WR's and RB's. However, it doesn't mean that the 1st round isn't.
The guy that stands out from that group is Henry Ruggs. The WR I warned everyone was overrated and the 4th best WR on Bama's roster - and was going to be drafted too high because of his speed. Gabriel Davis outperformed him and I had Gabriel Davis ranked significantly higher than Ruggs. Not to mention Justin Jefferson.
Winning organizations understand that the draft is about acquiring the best talent available no matter what position it is. If you're not competing for anything - you don't have any positions that are too good not to address with talent. Even Aaron Rodgers understands that now.
27% of the top 11 highest graded rookie WR's from 2010-2019 were drafted in the 1st Round (Odell Beckham, Mike Evans & Demaryius Thomas)
45% of the top 11 highest graded rookie WR's from 2010-2019 were drafted on Day 2 (Michael Thomas, A.J. Brown, Terry McLaurin, Keenan Allen & Chris Godwin)
In essence, 72% of the highest graded rookie WR's over the past decade were drafted in the top 75 picks - with nearly half of those drafted in the 1st round.
50% of the most receptions in the NFL since 2014 belong to WR's that were selected in the 1st Round:
Mike Evans (532)
Odell Beckham (487)
Brandin Cooks (483)
The other 50% belongs to WR's that were selected in the 2nd Round:
Jarvis Landry (636)
Davante Adams (546)
Allen Robinson (457)
There are outliers like Antonio Brown or Tyreek Hill that came off the board on Day 3, but they make up less than 10% of the big picture. A kid like Hill slid to Day 3 because he wasn't a very good person. Nothing to do with his talent. But when you're that talented even the NFL will only let you slide so far.
The rest of your post is fairly decent. Pitts is the best player in the draft and Day 2 is always a good place to snare top notch skill position talent that teams let slide out of the 1st round because they were all busy drafting Penei Sewell's.