If you want to respawn alive players, you need to pass True to the spawn function. That will force a respawn.
Your ES add-on doesn't work because est_spawn is a server command that is provided by ES Tools, which doesn't work anymore since 2010. Though, there are alternatives that provide the same commands. In your server console you should see "unknown command est_spawn".
I'm not quite sure what you mean. player.spawn() only spawns players that are dead, spectator or unassigned. player.spawn(True) forces a spawn/respawn. No matter if the player is alive, dead, spectator, etc. The game or map doesn't really matter. The map just needs a spawn point.