https://enclose.horse/ is a good game.
Install this as a TamperMonkey script and the optimal score for the current puzzle will be displayed in the bottom-right corner of the screen. When you switch to a bonus round, it automatically updates to show the bonus optimal score, then switches back when you return to the main puzzle.
Works for all bonus round types (lovebirds, costlywalls, etc.).
npm install
npm test
GLHF.