@burnout426 - Well, I'm laughing and scratching my head. When I rebooted my machine today, I only had one shortcut to Opera, instead of the two I had yesterday. Grimacing, I clicked on the one shortcut, and it opened - it was the old profile, with all the extensions I use and Sync is running.
Just to check, I looked at History, and was I shocked! It's all there!! Not only the dates I had used on the new profile, but history going back to February!! So, it seems no history was actually missing at all - it just wouldn't show before.
Sooooo, I don't know what happened, but it looks like Opera fixed itself!

Thanks again for your help - you got the 'ball rolling'!

@christomanifesto

UPDATE ::

"Good news everyone" - it took a while, but the bookmarks DID reload.😁

They are recovered. Praise the Lord!
And thank you Opera!

While I am aware that exporting and SAVING bookmarks (MANUALLY) is (supposedly) possible using the Opera browser for desktop/laptop computers, my question is:

Is there a way to export (and save to an html file) bookmarks from any of Opera's mobile browsers?

Real back-up always needs redundancy.

If you are reading this Opera developers, please understand:
Opera IS a great browser, but so many things can go wrong.
A simple export-to-html would solve the data loss risk, in my humble opinion.

With thanks,

Christo