I had similar issues where the Pi would not be reachable for minutes, due to the wlan carrier being lost. I have a Pi 4B, where the Pi connects to 5Ghz, Router is very close ~ 2m (signal strength -58dBm). Since i wanted to have better logs i updated to Octopi 1.0 in order to use the network watchdog. Now i still get wlan connection losse but they are quickly recolved causing no noticable connection outages when using octoprint.
Here is a log snippet of a connection loss on OctoPi 1.0
syslog_snippet.log (8.6 KB)
I really don't know what the problem is here. Wlan power save is permanently disabled, and i set a staic ip in dhcpcd.conf. I tried forcing the pi on 2.4Ghz with the addition of freq = ... to the wpa_supplicant.conf but without success.