Our big rotation has been what I've been thinking about this off-season as well.
There are three main paths:
1. Big move for an established big
The problem with this option is that there just aren't that many available. If they are, the entire league wants them. Jarrett Allen, Myles Turner, Naz Reid, etc. are all in this tier this off-season.
There are a lot of meh centers grouped around the middle (I call this the Gafford tier), but the gap between this tier of centers and the ones you can develop is not significant enough to trade big assets for.
2. Trade for a cast off big
This is not the exciting option, but it is viable. Zinger fits this mold right now, and that's why it may be worth just keeping him. Ayton, Mark Williams, and Julius Randle all fit this category of below-market-value-cost-for-production.
3. Development
Walker Kessler and Jabari Smith are both examples of players in this category, but both could be considered each of the last two as well. Any high draft picks for Queen or Malauch in this draft would require one of our top 5 players.
Fringe guys include players like Queta, Bol, and any number of other guys that NBA developmental coaches see the potential in that armchair scouts like myself can't.
We did this with Kornet, but his upside is somewhat limited. Knicks did this with Hartenstein. Wolves did this with Reid. Etc.
Of those 3 options, I think we need to take multiple chances on options 2 and 3. I'd keep Zinger if we can get under the 2nd apron a different way, give Queta a bit more burn this year, and sign one more minimum contract big that has some upside (or draft one).