The bets are determined by checking a wide variety of projections against my own knowledge of how players will be utilized given game context. The player prop lines were taken from this site.
When analyzing projections from fantasy sites, you'll often find that the projections are higher than betting lines, which will make you bet shit tons of overs. This is a common mistake. The projections are mean based, which tend to skew higher because the range of outcomes are not evenly distributed. (i.e., a running back on a good day could go for over 100 yards, but he would never go under 0... hopefully). If you find a mean projection lower than the Vegas line, the under is likely a good bet. To bet an over, the mean projection should be significantly higher. All bets below will follow that logic.
Saturday Slate
Geno Smith o220.5 passing yards -110 (FanDuel)
Christian McCaffrey u78.5 rushing yards -110 (FanDuel)
Justin Herbert u281.5 passing yards -120 (BetMGM)
Keenan Allen u81.5 receiving yards -110 (FanDuel)
Sunday Slate
Josh Allen u50.5 rushing yards -110 (PointBet)
Devin Singletary u46.5 rushing yards -120 (BetMGM)
Stef Diggs o6.5 receptions +115 (BetMGM)
Tyreek Hill o5.5 receptions +120 (BetMGM)
Dalvin Cook o68.5 rushing yards -115 (BetMGM)
Richie James u49.5 receiving yards -108 (Caesars)
Monday Night Football
Tyler Huntley o149.5 passing yards -120 (BetMGM)
Rachaad White o34.5 rushing yards -114 (FanDuel)
Leonard Fournette u28.5 receiving yards -110 (BetMGM)