Can PRB assignment be affected if the media on a link is limited?

Hello Everyone.
Query: can PRB assignment be affected if the media on a link is limited?
Lke a site configured with 2 carriers (B1+B20) is not reaching max throughput infact limited at 80 Mbps (max available link capacity).
But what is surprising is that PRB assignment is not full.
PRB on Pcell are full but PRB on Scell are mostly around 10.
Appreciate for some explanation, even if it is mandated that TX capacity bottleneck impacts PRB assignment

What is bw for band used?
Tx backhaul I think put no limitation on PRB assignment.

BW is 20 + 10.

Ok, so Pcell 100 PRB allocated for SCell, you’re not getting 50 PRB allocated. Is it correct?

Yes, correct.

Transmission quality is much related to PRB allocation.
If TCP packet loss or low bandwidth, incoming data to enb is not enough, then the number of PDCCH assignment & number of average PRB is small, low throughput.