not all powerline devices (and electrical infrastructure) are made equally. in my experience powerline can achieve much more than 50Mbit/sec. perhaps you have older technology?
heres some good tips on real world use/optimizations that could help:
https://micoolpaul.com/2023/07/10/how-to-actually-increase-powerline-adapter-throughput/
also remember, throughout and latency are two different things.
plus if you have a noisy environment (or lots of chatty wifi devices needing to stay connected) using wireless to back-haul wireless generally is going to be a bad time, no matter what brand/implementation you go with.