ad blockers are as easy as searching ublock in firefox addon stores.
Nowadays one does not need anything out of browser to stream content (except perhaps a vpn), so most likely your_favorite_show.exe(/apk) is malware. But even if it is legit but potentially contains malware you can always use a vm/android emulator (vm actually) depending on the software type.
Kodi + Fen Light plugin + Alldebrid + Trakt account. This setup is the easiest for people who don’t want to torrent or setup a NAS. It’s basically a pirated streaming service with the highest quality of streams. Alldebrid is a paid for service though but it is super cheap.
Oh, You want to use Firefox with ublock origin and a few other privacy add-ons if your not already, then just find a shady streaming site form the FMHY link that doesn't sketch you out too much. Your going to have to browse a few until you find one that's cozy and has what you want. You may also want a paid VPN for privacy if your worried, but I haven't heard of any one getting in shit for streaming and its very rare for torrenting.