Remote Play app sucks on my phone. It actually has microstutters and frame drops. I changed my router, connected via Ethernet, but it was useless. I can't change my wifi channel to less congested one because fuck tplink for not including channel 42 in their firmware. Also, one of my neighbours congests all the channels I can select which are not DFS channels. And on DFS side things aren't much better as another one congests 50% DFS channels. Also, my signal strenght is too weak -75 dbm unless I sit near my router, then it is ok. I also used wifi 6 on my phone, so PS Portal would be a nightmare on Wifi 5. Right now, remote play is playable, but skips frames, microstutters from time to time.
Even if you upgrade your network you may run into similar problems due to congested channels and signal strenght like me. Try to sort it or if you can't don't even think about buying a PS Portal.