I think you should remove the paywall for items and add new weapons.

I suppose that's a short summary of what I'm saying, so I will get into detail.
On every Furien server I’ve played on, the higher-damage knife and the WallHang ability have never been locked behind a paywall. These are typically standard features. However, the No Slowdown ability is alien to me and other servers.
I once played on an albanian, now dead server whose name I won't mention, it had amazing weapons, ranging from Janus-1, Janus-3, Janus-7 to even Janus-11. Besides the Janus weapons there was Lightning AR-1, Star Chaser SR, Blaster and many other weapons, most of which shot normal bullets but out of different guns.
These weapons, alongside the players were what kept the server going up until a couple years ago when the server became empty. I think if differentiate yourself from other servers in a good way, the server won't need to lock those features behind a paywall.