Enjoying the Chinese consortium that owns Opera too? I am not even joking here, given China's recent track record with WeChat I would think twice before using Opera to handle all your https (banking..etc.) traffic. Of course Chrome (US) suffers from somewhat similar issues. Firefox really has unique position in the market in that it's fully Open Source and has non-profit driven org behind it.
I am not a Chinese dissident, so Opera being owned by a Chinese company doesn't concern me. China has absolutely no interest in my activities.
I find your confidence in that to be rather touching. A testament to faith in humanity.
Opera is just rebranded Chrome, with some badly-advertised "VPN" slapped on top of it, a shadow of it's former self (the Presto version).
Opera is using Chromium's engine ("Blink"), but the whole UI shell ("chrome") is custom, with many UI conventions from old Opera.
I use that built in whatsapp a lot more than I expected. It's great. I love opera, it's my go to browser for dev.
That said, I'm definitely going to give quantum a try
the WhatsApp web feature is something that i never thought i use as much as i do. Really nice to have in the sidebar.