If you use firefox you can set up different profiles (this is different from account containers) and then set up a different proxy to work in each profile, so you can easily be on multiple accounts at the same time. I'm really tired right now so can't do a full write up or do sceenshots, but tl;dr is if you go to `about:profiles` on firefox you should be able to create a new one, and once you have you should be able to set up network settings with a proxy. For this I recommended a service like instantproxies to get them.