You'll need to see if there's some reason why your builder (?) stuck those super small orifices in there. Do you have solar panels up high? A pool pump powered pressure side pool vacuum? (Sp-p-puttering p's!)
The reason is, you may find you 'break' something by replacing the orifices. That said, creating backpressure like that is a common, but horrendously inefficient way of solving flow problems.
Are they really 1/4" orifices? That is almost certainly, way too small. Most PVC returns have replaceable eyeballs, like this one:
Hayward SP1419C White 1/2-Inch Opening Flow Inlet Fitting with 1-1/2-Inch MIP Thread
You can get *just* the eyeball, but you'd probably have to go through a dealer locally, and it might be cheaper to order the whole ring, body and eyeball, as shown in the Amazon link above.
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