All that to say, manager Gabe Kapler will have lots of options when creating lineups this year. Here are projected starters with career OPS and wRC+ against platoon (note: Joey Bart, Thairo Estrada, and Mauricio Dubon have too few MLB plate appearances to assess their platoon preferences).
San Francisco Giants Starters vs. RHP
C Joey Bart
1B Brandon Belt (.848 OPS, 132 wRC+)
2B Tommy La Stella (.761, 107)
SS Brandon Crawford (.741, 100)
3B Evan Longoria (.784, 113)
LF LaMonte Wade Jr. (.835, 124)
CF Mike Yastrzemski (.857, 126)
RF Joc Pederson (.832, 123)
DH Darin Ruf (.696, 92)
San Francisco Giants Starters vs. LHP
C Joey Bart
1B Brandon Belt (.756, 110)
2B Wilmer Flores (.823, 119)
SS Thairo Estrada/Mauricio Dubon
3B Evan Longoria (.871, 132)
LF Darin Ruf (.940, 153)
CF Austin Slater (.853, 131)
RF Mike Yastrzemski (.772, 108)
DH Curt Casali (.756, 103)
Those are two very productive lineups. If rosters are expanded to 28 to start the season that likely opens the door for Duggar to make the team. In that scenario, his career .767 OPS and 107 wRC+ would fit nicely in centerfield versus righties with Pederson moving to the DH role.
Nobody predicted the Giants would have the best record in baseball in 2021 and few will make that projection for this season. If they remain healthy and their excellent rotation performs as expected, they should, however, compete for one of the six NL playoff spots in 2022.