My question would be why those fans? They are noisy and produce very little airflow (CFM) and the static pressure is super low... if you want the air to move over heatsinks on the PCB you'd also need to make some air guide from cardboard or plastic.
Maybe consider some blower fans which can do way more static pressure so the air can be pushed over those heatsinks
For example :
https://www.tme.eu/en/details/mf50151vx-a99/dc12v-fans/sunon/mf50151vx-b00u-a99/Will use more surface but you could lift it above the pcb surface on hex standoffs - and you can use two pcb holes to screw the standoffs or directly the cooler to the pcb (but I'd probably use some rubber things to reduce vibrations)
For example you could have one of these blower fans above the two heatsinks on the left side in your picture and you could have a cardboard guide or something to make the air flow over those heatsinks.
Also ... how TALL is the box your pcb is gonna be in... looks like it's gonna be AT LEAST 40mm tall due to these fans you chose. If the box is closed, sounds like maybe you could have standard 92...120 mm fans but maybe 15mm thick instead of 25mm, and mount them on one side of the box and push air inside the box, and have ventilation holes on the other end of the box and the air pushed in by the fans would naturally go over the heatsinks and come out through those vents on the other side of the box..
Think computer power supplies and how they use fans to push air into the psu and out the vent holes.
ex 80x80 x 20mm tall :
https://www.tme.eu/en/details/me80201v1-a99/dc12v-fans/sunon/me80201v1-000u-a99/or
https://www.tme.eu/en/details/me80201v3-a99/dc12v-fans/sunon/me80201v3-000u-a99/Also for a 2kw prototype maybe you guys could have picked heatsinks more suited for forced air cooling (ex extruded, with more vertical or horizontal fins instead of those with 'spikes' around the part.
The layout of the pcb looks bad, but too little in the picture to tell for sure... would love to see more of it.