Connections to this router have been working Ok for the bot until recently ?
Assuming your bot is a Genesis model, yes, the Linux buildroot kernel for the Raspberry Pi model 3 does not yet support all Wi-Fi 6 features, in particular, WPA3 security.
Maybe check that the Eero Pro is configured to allow WPA2 on the SSID used for the bot.
5 GHz channels should be fine provided that you’ve set up your Wireless Regulatory Domain Country Code correctly during Configuration.
 Just checked my Express bot and discovered that the Raspberry Pi Zero W in there is set to Wi-Fi Generation 4 ( hw_mode N ) :
iex(email@example.com)5> cmd 'wpa_cli -p /tmp/vintage_net/wpa_supplicant status'
Selected interface 'wlan0'