It seems like the best approach is going to be a mix of the solutions you proposed. Bringing in more players is the best (like you mentioned), but also the most difficult as we've seen from the team's struggle in retention numbers. Reducing costs seems as though it has reached diminishing returns as well unless we want to disrupt the current productivity of the team (which has been great this past year), so I would count that out. That leaves a mix of the rest of them.
Increasing utility through more sinks should be something the team is doing automatically (Land, guilds, etc) so no need to focus extra on that as it will come in time. Flow adjustment seems to be addressed as well as I believe we are focusing on paying the team in other tokens besides DEC and exhausting those before moving to DEC. So this leaves treasury management and the external/bridge sources you mentioned.
A part of me doesn't want to get too far ahead of ourselves. The team has a significant runway now (2 years) to start delivering on some of the solutions. With everything that is already in place, I say we give it 3 months before taking any concrete actions to see how the situation develops. Maybe I'm being complacent, but I also don't think another 3 months will do much damage - if anything I think certain things may resolve themselves.
RE: DEC Cycle (Re-cycle?)