@Justly0250

Firefox Multi-Account Containers:
sandbox tab containers to isolate sites.
https://addons.mozilla.org/en-GB/firefox/addon/multi-account-containers/

Temporary Containers:
Open tabs, websites, and links in automatically managed disposable containers
https://addons.mozilla.org/en-GB/firefox/addon/temporary-containers/

Dark Background and Light Text:
dark mode all the things
https://addons.mozilla.org/en-GB/firefox/addon/dark-background-light-text/

@Justly0250

uBlock

The Internet is not the same without it.

Some of these are specialized tools, but to start, I make big, big use of dedicated containers, Google, Amazon, Reddit, Pixiv, Tumblr, and Discord. Sidebar note, uBlock Origin, NoScript, Bypass Paywalls Clean, Container Sidebar, Downloads Sidebar, Get RSS Feed URL, Pixiv Toolkit, FediShare, Tumblr - Post to Tumblr, Twitter Gif & Video Downloader, and Video Downloadhelper