Using fWAR, here's the 2019 lineup vs. the 2020 lineup.
2019
C - James McCann, 2.3
1B - Jose Abreu, 1.9
2B - Yolmer Sanchez, 1.0
SS - Tim Anderson, 3.5
3B - Yoan Moncada, 5.7
LF - Eloy Jimenez, 1.9
CF - Adam Engel, 0.8
RF - Ryan Cordell, -.2
DH - Yonder Alonso, -1.3=
2020, using 2019 numbers and Steamer projects for rookies
C - Yasmani Grandal, 5.2 (+2.9)
1B - Jose Abreu, 1.9
2B - Nick Madrigal, 1.7 (+.7)
SS - Tim Anderson, 3.5
3B - Yoan Moncada, 5.7
LF - Eloy Jimenez, 1.9
CF - Luis Robert, 2.3 (+1.5)
RF - Nomar Mazara, 0.5 (.7)
DH - James McCann, 2.3 (+3.6)
That lineup is 9.4 fWAR better.
Now, Grandal, Anderson, Abreu, McCann, Jimenez and Moncada could all regress. But conceivably, Moncada, Anderson, Mazara and Jimenez could improve drastically. This is also assuming Madrigal and Robert have ok rookie seasons, when they'll both be capable of much more, especially Robert.
The lineup upgrades alone are nearly enough to get this team to .500. That's not quite playoffs, but it's something to be positive about when we still have a couple months of offseason left.