Through some trial and error I've been able to get the printer connected. For anyone else who has this problem I hope the below helps.

- Printer would not connect to main network with 2.4ghx and 5ghz channels turned on. Every attempt saw the printer fail to be recognized

- I enabled a guest network with just 2.4ghz but no luck trying to connect. Security setting was on the default value of WPA2-PSK only.

- I updated the guest network to have no security (still 2.4ghz only) to test if the problem was related to that. This time the printer did connect and was recognized. I quickly turned the security back on obviously after the test.

- Then, on the guest network still with only 2.4ghz, I changed security to WPA2-PSK and WPA-PSK setting. The printer went through the connection process and this time asked for the wifi password to be input (1st time seeing this) in the Canon PRINT app. The printer eventually was recognized and I've been able to print what I needed at last.

Hope this helps anyone who has the same issue in future!