IMHO it is best to start with a working game, your second machine can be a fixer

Nothing worse than an unplayable game taking up space
Also there are games that can be fixed (you CAN buy parts) and games that cannot be fixed (parts are NOT available, and will never be)


As for finding games, work out what era games you like, modern DMD , late 70s solid state, electromechanical.
Then make a list of 6 games that you like and keep an eye out for them