Hello everyone! First of all, I apologize for my English. In my google search I came across this page and I found the topic to be very interesting.
I tell you my experience when browsing with Windows XP. Firstly the supported browsers were: Mozilla Firefox 52.9.0 with uBlock Origin v1.17.4 Firefox (addons signature must be disabled from about: config) and SRWare Iron 49.0.2600.0 with uBlock Origin v1.16.20. For SRWare to work I had to install the certificates, I put the certificates of my Windows 10 and perfect.
In both navigation without problem, youtube works very well like the other pages. Of course, in SRWare, it appears that the browser is going to be deprecated, but it is a warning.
As for security, Avast Free Antivirus v18.8.2356 still receives updates, Malwarebytes 3.5.1.2522 and SUPERAntiSpyware is supported.
Regarding the 360 browser, which appears with so many names, YouTube has some lag, because it consumes more resources. Use the latest version I found, 360 Chrome Browser v12.0.1386.0. The Russian versions make no difference, except for the installer language and putting the interface in Russian. It strikes me a lot as a chromium browser that has XP support is so hidden. I don't see anyone doing a translation to different languages, much less have support for spell checking.
I tried several like Maxthon but navigation is slow and does not support chrome addons.
I also tried the famous version of chromium 75 for XP without results, it is still not supported.
I hope someone can rescue the 360 browser and provide translations into more languages.
Regards.