While logging chat, IP's and system specs is not needed (for the most part) i'd urge you to reconsider logging other data.
Depending on whether or not you will be offering any kind of support in the future, logging serverwide public channels (such as broadcast and help for example) as well as system logs (system, quests, etc) would be incredibly helpful to have on hand. All of these can help fix possible issues for players, and they will also help you combat abuse, cheating and - if the server becomes popular enough - gold farm/selling activities. None of these logs would form an issue GDPR wise as they can be considered necessary to make sure the servers can run correctly, if that's what you're worried about.