i dont understand what it is then. every single piece of artwork ive seen for it makes it look like a medieval fantasy game. what makes it not one?
theres no defined time period, its entirely fantasy. some artwork of specific locations may be partially gothic/medieval architecture inspired, but of all the 140+ champs and 6-8 major regions, only one of each can be arguably called medieval/heavily medival inspired
ik this might be much for you to take a look at, but you might be interested in the map the lore writers and artists put together. it should clarify why it isnt medieval fantasy and rather just pure fantasy
https://map.leagueoflegends.com/en_UShighly suggest bilgewater and piltover as places to start in cause imo the art from both regions are the best