Hey there OP, here's some things that helped me optimize my Ragnarok map. Having read your other comments I do see it's issues with your players as well, so I'll give two kinds of advice: Server side and client side.
Client side is my usual go to when someone has a problem. What's your computer's specs? Are you running 8gb ram? If so, you need more Ram. That's not enough for ark since your GPU/System is also using that ram. I doubled my ram and I very rarely get DC/d or lag anymore. Additionally, AMD or Nvidia? AMD is finicky and you need a special command ran via steam at the start of ark that greatly reduces issues that occur with an AMD card and Ark (Wildcard please).
Verify your files!!! Do this weekly, make sure you have all your files validated in steam. This causes SO many problems and is fixed so easily (you just have to wait!).
Server side? It could be different things! What mods do you have? Who is your server provider? What settings have you adjusted. Someone suggested halving your dino count and this could help, but it severely effects your experience. I personally suggest removing dinos that you hate, since the kibble doesn't work the same anymore. This doesn't effect your dino counts of other dinos and everyone ends up happy on your unofficial server! Ignore people who mock others who remove dinos, it's your unofficial server, do what you want.
Check with your server host, there might be something they can do to help you out. When I've exhausted all my sources of 'fix it' I go to my server host. They often have solutions. If you are server savvy and you don't happen to have a host, but instead you are the host with your own machine, check your server machine's specs and make sure its up to the task properly to host everyone trying to play! I don't know enough or anything about hosting your server with your own machine, so if this is the case, take a day or two to look into it and make sure everything is right as rain.
When was the last time you did a dino wipe? Do them regularly.
In an area with intense structures? That's causing the lag since it has to load in the base (especially bad if you have low ram. There's an area of our map with a building that one of my server members just cannot go near).
Most often times that you get crashes from an unofficial that effect everyone it's your mods. Your mods could be outdated or causing conflicts with other mods. Double check them, if you have them, and make sure they are compatible or in the right load order. I hope this helps and you find a solution to your lag ❤️