Most likely because gmod is dead

@cdozhytb all of that was from the original code. Nothing you brought up was changed or added in this version and there haven't been any complaints or comments about that stuff on that version

If it's the code from that "based on" addon... I just don't want to subscribe to find out...

You should never send the whole table to the client (this is the DoS part). I suggest you to move your data to SQL and to only send stats of a specific player (the only one who requested them). Also implement some sort of caching mechanism or just never receive anything on server from client and send a net message on each round end - this part is also malicious in your current realization, because right now you immediately update your stats table which means that players can see whos killing counters are updated (ez traitor revealing strategy btw).

I don't see any reason why this should be an ENT, but it's not the main problem.
Unprotected unoptimized networking - you really shouldn't subscribe to this addon. Anyone can delete this statistics and anyone can easily DoS your server (two reasons to not only unsubscribe, but to report).
Equipment stats? Use server-side hooks and function only (because its server-side statistics). If you must use client-side - something is wrong with your realization. Literally anyone with injector can spam servers with nils or just random huge strings by your TotalStatistics_SendClientEquipmentName net message.