I've suffered this since taking on Monterey on my M1 Air (no wifi issues with Big Sur). I read it was to do with the 80MHz bandwidth wifi channels and after changing to 20MHz on both bands in my Aruba AP-105's, no further issues with the drops. Still getting log messages for SymptomsMgrDNSFailureSymptoms and sharingd/rapportd not entitled for com.apple.wifi.join_history. I do see a quick drop with the log "Apple80211Set:10289 Processing APPLE80211_IOC_ROAM" but not enough to drop shares or cause ongoing copies to fail etc. Other Macs running Big Sur and iPad mini 5, iPhone mini 12, no issues at all with the wifi even before the change.