Hey dude! This was a very comprehensive criticism, but I'd like to add a little bit onto that, if it's alright with you!
1. The actual reccomended party size in DnD 5e is 3-5 players, with 4 players falling smack-dab in the middle of that. As a 5e DM who has been playing for, what, 5 years now, most of my parties have been in that range.
That's misinformation.
The recommended party size is 4-6 with 5 being in the middle.
Curse of Strahd: "...for a party of four to six characters..."
Storm King's Thunder: " . . . adventure for four to six player characters"
Descent into Avernus. See the Avernus discussions on Reddit:
https://www.reddit.com/r/DescentintoAvernus/comments/ejqf6t/ideal_party_size/Also check out any critical role episode.
