My apologies for not making myself entirely clear: even if you have no addons whatsoever, and you open Firefox and try to navigate to some bare-bones text-only website, even that is extremely slow on the 2GB Pinephone.
However, I would question whether uBlock Origin degrades performance – my own experience running Firefox on low-memory platforms like netbooks and the Raspberry Pi suggests that is not the case. Yes, addons use some amount of RAM, but if they prevent the device from loading a modern advertising-based webpage where the ads and analytics run into the many megabytes and the useless Javascript is CPU-intensive, it seems to work out as a net benefit.
However, I would question whether uBlock Origin degrades performance – my own experience running Firefox on low-memory platforms like netbooks and the Raspberry Pi suggests that is not the case. Yes, addons use some amount of RAM, but if they prevent the device from loading a modern advertising-based webpage where the ads and analytics run into the many megabytes and the useless Javascript is CPU-intensive, it seems to work out as a net benefit.