Stocking

Hope this in the right place if not sorry

Can I put 2 more parrot fish in my tank
500L 60" long 30" high 24" deep
Fluval FX4 filter
2 parrots
20 Boanasaries Tetra
20 Rummy nose Tetra
10 Gold Barbs
10 Cardinal Tetra
10 Silver tip Tera
2 Bristle Nose Plec

@Shelly I don't keep Parrots but this sound like it is stretching things a bit. The general recommendation I see say 'generally social within species' and you already have quite a mixture in the tank, the additional competition for space might just tip the balance.
I would think the filter would also start to struggle as their bio load is shown as heavy. You could add more filtration but there would still be a compatibility / fish personality risk, do you have a viable backup plan to rapidly move all the non-parrots if things don't work?