I tried opera android v.21 doesnt work too. Then update to v.29 and thats working till now but 1 missing features is i cant download youtube directly from opera.
But other tube website still working & can be downloaded.
Ussually i use site: savefrom.net in pc/laptop, but opera android didnt worked.
I now understand, its google itself blocking using old version. Yah bussines struglle i think.
Opera is most android browser i use, still can work with 50 tabs opened no lag (if u have big gb space internal).
I surely missed feature for save to .mht file that can be open in pc. hope opera will added that offline savefile features