I suggest you find an ally. There must be someone among 25 units. Together you can put a motion in opposition or at the least proof-read each others work after writing a statement in opposition to the motion. The strata manager should agree that a statement in opposition to the motion be included with the meeting papers along with (I would assume) the EC’s statement in support of the proposed budget that includes this particular expenditure item.
As an aside, I do sometimes wonder what I might get paid for all the times it has been easier to organise something myself (I am treasurer) rather than try to explain it all to our managing agent, even though I am generally happy with their service. I am sure our OC would not agree to spending that much on any EC member or the chair or all of us on the EC, and we have a much larger OC. Some ECs, even with a manager, do a lot of unpaid work, and sometimes I think an honorarium might be nice, but $21K does seem excessive.