I'm in a guild with 1000 members and the FillPlayerBank() that is called on every "GUILD_ROSTER_UPDATE" is inefficient and causes massive lag spikes.

Either find a way to preserve the scrollframe and playerlabels so they are not reconstructed every call or add a manual refresh button. Unless you can think of a better way.

For now I've edited the addon myself and it only will call FillPlayerBank() once per /reload

Good call-out. I'm not in a big guild so I don't experience this issue. I'll find a way to better hold the state to prevent full redraw each update.

Fixed in 69aefdf -> v1.1 on curseforge.