So this isn't Underdog, but rather DraftKings, as they have a promo that ends in a couple of days that your first entry in their $10 Best Ball Millionaire competition (I don't know the exact name), you get back 10 DK dollars, so I basically took a freeroll.
I ended up drafting 10th overall out of 12 and here is the team I ended up with (20 total roster slots, DraftKings full PPR scoring, start QB/RB/RB/WR/WR/WR/TE/Flex).
QB:
Tua Tagovailoa (7, 82)
Anthony Richardson (8, 87)
Sam Howell (14, 159)
Gardiner Minshew (20, 231)
RB:
Jahmyr Gibbs (4, 39)
Alexander Mattison (5, 58)
Cam Akers (6, 63)
Devon Achane (10, 111)
Elijah Mitchell (11, 130)
Cordarrelle Patterson (16, 183)
WR:
CeeDee Lamb (1, 10)
Garrett Wilson (2, 15)
Calvin Ridley (3, 34)
Odell Beckham Jr. (9, 106)
Marvin Mims Jr. (15, 178)
Rashid Shaheed (17, 202)
Josh Downs (19, 226)
TE:
Gerald Everett (12, 135)
Sam LaPorta (13, 154)
Jelani Woods (18, 207)
Basically, I drafted CeeDee and Wilson at the Round 1,2 turn with the plan to stack with Dak and Rodgers in the mid-rounds. Ended up getting sniped on both QBs. Dak was ADP 91, I targeted him at 82, and he went 78. And the team that took him had just taken Lawrence the round before!
At that point, I panicked. I figured 82 was way too early to get Rodgers, so I went with Tua, even though I wasn't able to get either Dolphins receiver earlier. At pick 87, I didn't see any players I liked at that slot, so I ended up reaching for Richardson, which I wasn't planning to do (At the end of the draft, I ended up creating a Colts "stack" by taking TE Jelani Woods and their 3rd round pick WR Josh Downs, who profiles as a slot receiver. I also took Minshew with my last pick in the event Tua gets hurt and Richardson gets benched.). I was planning on taking Rodgers, with an ADP of 111, at 106, which meant I would have gone QB in three straight rounds, but he ended up being picked at 100.
I like my RBs and WRs and figure either this team is going to be a unicorn and advance out of my 12 team group or is going to finish dead last. Either way, I don't think I'll be doing any more Best Ball drafts. I'll stick with regular DFS and my two season-long redraft leagues once the season starts.