Tor Browser 12.0.4 introduced a new "Security Slider" (Standard / Safer / Safest). For older hardware, "Standard" is fine. For maximum safety against exploits known to this version, set it to (disables dangerous JavaScript on non-HTTPS sites).
Using Tor Browser 12.0.4 today is highly discouraged by the Tor Project for the following reasons: Index of /tor-package-archive/torbrowser/12.0.4 Tor Browser 12.0.4 Older Versions for Windows
Instead: