The phone or browser may be using DNS over HTTP (aka DoH), check if you can disable it for the wifi network. You may have to disable it on the phone or browser to get your desired behaviour - look up directions for your browser.

This. Basically few addons are ‘fire and forget’, almost all of them need some sort of configuration that’s listed in the Documentation tab, or in the add-ons repo. You’ll need to read up on it and look at the Configuration tab to set whatever you need to allow it to work.

Right now - easy, with the difficulty going up over time as the main Chromium codebase continues to change (and especially as it gets security updates). I think I’ve read that some variants (Brave?) have committed to supporting ManifestV2 for as long as possible, for instance with their own fork.