How to reduce internet lag for multiplayer servers?

I’m not expert but you should make sure you are replicating (on server) only blueprints that realy require it. You don’t need to replicate cosmetic blueprints, you can chose some class to be done only on server/client.
Then you can try to run Server and launch some other game clients on same PC and connect them localy if it will lag then you will be sure that your internet isn’t good for hosting.

I really need to reduce lag on my game. I’m currently only using listen servers but plan to use dedicated servers eventually. It’s a sports game which means it really needs a good connection for the gameplay to feel good. Currently, it’s mostly unplayable due to the amount of lag. I believe my blueprints are optimized but I’m not an expert so I’m not sure. I’m just hosting the servers from my personal computer, and my internet is okay but not that good. I imagine that could play a big part in the lag. So what are some ways that I can improve this to reduce the lag?

Also, how big of a difference would it be if I setup a dedicated server from a source code build and paid a company to host it? Is there some sort of technical difference regarding the ISP that a server hosting company would have to improve connection that I don’t with my personal internet? Any info is appreciated.

As Przemek said replicate only things you need, make client do all (that it can) things that does not effect gameplay and UI should be fully on client side and optimizing game overall should speed up things, remember that server is the one processing game state so if this is slow it ends up to lentecy, also server specs effect that too ofcorse. If you mean ping, connection have natural lentecy since data routing takes time too, ping your server to see what lantecy you have and compire it with the ping in the game.