i use an sql database for all external data / stats (player data/info, kills, stats, high rounds, time, server status, player count, server use, reset times, etc)
I used the fileIO method but the database got way too big and bogged down. It was also cumbersome to sort through and very slow. SQL is super fast and easy to sort and the best part is the work is done off server and then sent to whatever source asks for it (in game, the discord bot, webpages, etc)
It was a must for the number of entries my database quickly grew to.
Edit: it helps that i was very familiar with SQL but if you are not, i think it is a relatively easy thing to learn and popular enough that any simple google search can yield the results you need on the proper way to word queries.