Firefox is the only way.

I hate everything you said here.

If you use Firefox nightly (and maybe some of the other beta branches too, I'm not sure), there's a way to get any extension, they just might not work properly. I haven't really had issues with nightly, despite it being such a bleeding-edge build - although I would recommend keeping a backup browser since sometimes it decides to just stop working

• Bromite hasn't been updated since January, you are running an outdated browser with potential security vulnerabilities
  • There is an updated Bromite fork called Cromite
• Mozilla might finally open up extensions on mobile again

I've been using Bromite too.

Can anyone suggest a site to sideload firefox? Very unsure about what's trustworthy any more.

You can install any extension you want on the Dev version and some forks like mull by setting a custom extension collection. It's a bit of a pain but it works.