A simple script to let you easily switch themes.
Erase all colors from your alacritty.yml file, take note of the last line number of the file. Like 502 or so.
Add that line number to this script LINE_NUM= like LINE_NUM=502.
Keep a directory of theme files handy like in ~/.config/alacritty/themes
run ./alacritty-theme-switcher .config/alacritty/themes/Your-Theme.yml
replace Your-Theme.yml with your theme file.