Here are some of the 146 (!) fares ranging from $248 to $1638 plus taxes, for departing 12/22 EWR to SDQ. Whether these fare codes are available or not (X v.s. N vs. Q etc.) are up to the airline. Looking at fare basis , not many are - on CO only C,H,K and N classes. Note from JFK the fares, all 197 (!) of them are almost the same range from low to high.
Waiting will not likely incrase the number of seats nor drop the price in a limited supply business. When I went to the DR for Xmas I bought a ticket no later than October and even that was full fare business class as there were no seats even at top price later.
Only CO would be non stop.
X0APOW CO X One-Way 124.00 (USD)
N7C1SOW AA N One-Way 129.00 (USD)
W7APOW CO W One-Way 144.00 (USD)
L7SDQO US L One-Way 144.00 (USD)
S7CC25 AA S Round-Trip 298.00 (USD)
I7APOW CO I One-Way 154.00 (USD)
S7CC25O AA S One-Way 164.00 (USD)
S7SDQ US S Round-Trip 318.00 (USD)
SAA3CD AA S One-Way 169.00 (USD)
V7CC25 AA V Round-Trip 338.00 (USD)
W7CRB US W One-Way 169.00 (USD)
V7CC25O AA V One-Way 184.00 (USD)
I0BN CO I One-Way 184.00 (USD)
VAA3CD AA V One-Way 189.00 (USD)
W3CC25 AA W Round-Trip 378.00 (USD)
V7CRB US V One-Way 189.00 (USD)
U0BN CO U One-Way 194.00 (USD)
Q7CRB US Q Round-Trip 388.00 (USD)
W3CC25O AA W One-Way 204.00 (USD)
W7CRB2 AA W Round-Trip 398.00 (USD)
V0CRB US V One-Way 199.00 (USD)
O0BN CO O One-Way 204.00 (USD)
WAA3CD AA W One-Way 209.00 (USD)
L3CC25 AA L Round-Trip 418.00 (USD)
L3CC25O AA L One-Way 224.00 (USD)
HHX390 US H Round-Trip 440.00 (USD)
LAA3CD AA L One-Way 229.00 (USD)
N0BN CO N One-Way 229.00 (USD)
Q3SDQO US Q One-Way 229.00 (USD)
HHW390 US H Round-Trip 475.00 (USD)
QHX7NCB DL Q Round-Trip 487.00 (USD)
H3CRB US H Round-Trip 488.00 (USD)
V3CRB2 AA V Round-Trip 498.00 (USD)
HHX390 UA H Round-Trip 498.00 (USD)
VHOL14N AA V Round-Trip 506.00 (USD)