Raspberry Pi 3B+ Access Point: unreliable

Hi

I have installed OpenWRT on a Pi 3 B+ as WiFi router.
Everything works well until it does not.

After a while (minutes, hours) some of the devices cannot be pinged.
But they can come back.
Even if their connection is on a working some of them cannot be pinged at times.

Their network is never "lost".

A Chromecast seems to be the most reliable, but tablets and phones (Android 7) can disappear altogether.

I tried to do the same even without OpenWRT and I got comparable behaviour.

Have people found the Pi 3 B+ reliable as a wireless access point?

I haven't tried it, but I read in multiple posts on the forum that the performance of the Wi-Fi of the Raspberry Pi isn't really good as an AP running 24/7 (and neither is USB wireless adapters, as I read). People use the Pi as a router for the CPU and RAM advantage, but ideally you would need to connect an AP to provide adequate wireless access.

I have the same feeling.
On the 5Ghz band it seems to works better, but it might just be a bit of random behaviour.