It would be better to create a save system overall.
But when it comes to player start, all of them has a ‘player tag’ usually empty. You can fill that tag with whatever you want (name, numbers, for example ‘checkpoint01’) and you can call using ‘FindPlayerStart’ (fill the ‘incoming name’ with the tag you previously set) and the return value you can set at ‘Restart Player at Player Start’. You can do this inside your game mode.
However, I don’t think that will fix your problem enterily. I think you need to set a save system to keep track of the players checkpoint properly. You can use what I said above, but it would work better with player system. You could save a integer inside you data table and using the return value you could convert to string and use on ‘FindPlayerStart’ (but the ‘incoming name’ set on PlayerStart should be numbers as well).
For example, I’m using this for my multiplayer game. On lobby, I want the host player to be at the center, so I use these to select which player start will be filled first.
In my head, this could work perfectly. But in case you need more assistance and don’t know exactly how to set this, I’d recommend watching a tutorial series of Save Game.
Ryan Laley channel has some awesome content. I’ve learned many things from him. Matt Aspland too! You don’t need to do exactly like them, but you’ll learn from them the base and you can implement with whatever you want.