Personally I use ~/opt//bin where ~/opt is a ‘one stop shop’ containing various things, including a symlink to ~/local and directories or symlinks for things that don't play well with others (e.g. cargo, go), and an ~/opt/prefer/bin that goes at the start of PATH containing symlinks to resolve naming conflicts.
(Anything that modifies standard behaviour is not in PATH, but instead a shell function present only in interactive shells, so as not to break scripts.)
Unix lore: Early unix had two-letter names for most common names to make them easy to type on crappy terminals, but no one* letter command names because the easier were reserved for personal use.
What's the difference between opt and local?
I thought was for mixin externally provided systems like Homebrew, local is for machine or org-level customizations, and ~ is for user-level customizations.
/opt showed up as a place for packaged software, where each package (directory) has its own bin/, lib/, man/, and so on, to keep it self-contained rather than installing its files in the main hierarchy. ~/opt is just a per-user equivalent, analogous to /usr/local vs ~/.local.
The advantage of /opt is that multi-file software stays together. The disadvantage is that PATHs get long.