Assuming the Dubnyk and Donato trades were related, I guess what it comes down to is a comparison between these two scenarios for 20-21:
Devan Dubnyk
Ryan Donato
2022 seventh round draft pick (Minnesota)
or
Aaron Dell
2021 third round draft pick (Pittsburgh)
2022 fifth round draft pick (San Jose)
$3,266,667 more cap space
Now, if the Sharks were able to use that additional cap space to sign Smith, Toffoli, or Dadonov, I'd much rather have the second package, but the difference is primarily in the draft picks, rather than the on-ice product - you get a legitimate forward for somewhat higher cost than Donato will likely wind up incurring (unless he totally flunks), possibly a second inexpensive forward (for example, Namestnikov or Fast at $2 million - the actual player doesn't matter so much as the cost), and two mid-draft picks, and possibly a better backup goaltender.
On the other hand, it's possible that done of the better free agent forwards was interested in San Jose, and it wouldn't be worth paying for any of them to change their minds, I think. Donato looks like a decent forward who will likely cost less over the next three to four years (assume Donato has a pretty good season, say 0.5 PPG - what will he likely command as an RFA, maybe $2.5 million and possibly less with the pandemic hammering league finances?). If Donato works out, or Dubnyk is as good as Dell and at least acceptable (say .905 SV%), then this scenario probably works out fine, and if none of the good free agent forwards was interested in San Jose, this is probably about the best we could expect.