I don't know if the offense is necessarily going to be that much worse, and I believe it's still going to be a real team strength for next season.
Bo is a big loss, but the projections call for a 117-121 wRC+ range for him, and if Okamoto transitions well to MLB without a huge learning curve his 113 wRC+ projection seems attainable and that would replace most of what Bo provided with the stick. For what it's worth the ZiPS projections for Bo and Okamoto are an identical 118 OPS+ so this may be more of a 1 for 1 replacement.
I expect a bounceback season from Santander, although it remain to be seen how much of his previous production he is able to recapture.
I seem to be in the minority in that I don't expect Springer to turn back into a pumpkin, but in the case he takes a large step back with the bat I am hopeful that a better Vlad season can pick up some of the slack.
I believe simply receiving better health from the position player group can also be a large difference maker, as Varsho missed half of the season, Santander had his season ruined completely by injury, and I suspect that Gimenez was largely hampered by a wonky ankle for much of the season as well which made it all but impossible to successfully implement the tweaks that Popkins desired with him utilizing his lower half more effectively.
Having a full season from Barger vs struggling rookies in Roden and Wagner should help as well.