If you ever want to get as many players as you did before you're going to have to reset/re-release. The only people who don't want a reset are the current players (15 players). If you're trying attract new or old players back to the game, they're not going to play it if they see people in max gear. You have no potential to even aim to hit 50 players if you do not re-release and that's the harsh truth, you have to accept it. Personally, i'd say to release a beta period 1-4 weeks and then start and advertisement campaign. Do discord invite competitions etc.
What killed this game was the developers lack of interest in new players. When I played, I told them that the drops were way too hard to get and similar to 07, they didn't seem to listen, but only to the few people who thought it was fine. Now look what it did. It killed the game so quickly and they fixed that mistake after the damage was already caused. Tldr; look at the game as if you're a new player looking for a server, not an existing player. You're attracting new players, not the ones that are already playing the game.