Sorry, but render distance is bar none one of the most taxing settings for a multiplayer Minecraft server, with exponentially greater server impact the higher you go. Multiplayer servers used to run with a vanilla setting of 10, but that hasn't been feasible in years. I don't think the server has been able to support a setting even that high since I first joined back in Minecraft 1.7, and updates have only brought that lower and lower. The way Mojang has been developing the game, it is extremely unrealistic it will be able to be turned up anytime in the near, or even distant future, until they finally make the game multi-core.
In short, we'd love to, but we can't. It just isn't an option.
In short, we'd love to, but we can't. It just isn't an option.