• You are able to auto-kick level or perk without mutator as Ranked Server.
• I'm not original creator, I fixed a issue and improved, add perk-kick features.

Original script is here. (not available)
https://forums.tripwireinteractive.com/forum/killing-floor-2/killing-floor-2-modifications/general-modding-discussion-ad/beta-mod-releases/115511-webadmin-auto-kick-players-by-perk-level

1. Install Chrome* or FireFox. *Recommend Chrome
2. Install browser addon Violentmonkey.
3. Download latest release zip file.
4. Import the zip file from Violentmonkey setting.
5. Extract the zip file.
6. Backup and OverWrite 3 files:
   location: <KF2Server>\KFGame\Web\ServerAdmin
   • console.html
   • current_players.html
   • current_players_row.inc

1. Launch KF2 Server.bat
2. Open brower FireFox or Chrome.
3. Move to WebAdmin. (default: http://localhost:8080)

Click MANAGEMENT CONSOLE in WebAdmin.

• ALLOW MINIMUM PERK LEVEL
  A player below this level will be kicked.

• ALLOW MAXIMUM PERK LEVEL
  A player above this level will be kicked.

• KICK PERK
  Checked perks will be kicked.

• ALLOW ALL PERKS FROM LAST WAVE UNTIL THE BOSS WAVE
  If checked Enable, all perks are allowed between last wave and boss wave. (default: unchecked) But keep level-kick. When players reach last wave, following message will be announced:
  Allowed All Perks from last wave until the Boss wave.

These settings will take effect in a few seconds after being changed.

It dose works if you see a number 1 with Violentmonkey icon.

Keep open browser to work auto-kick script. If you close the browser, the script will not work.

It is not a bug but a feature. All players name are shown as anonymous because to avoid a bug which would not work by GO button. This is not my script bug. This is a known bug caused by the KF2 server not assuming player name whose multibyte-characters. That is why this is not my script bug.

Yes, if your server under heavy load, Tampermonkey could be better.

Yes, the setting is independent per url and is stored individually.

I fixed and improved things are following:

• Previous auto-kick script could't kick specific player whose name is multi byte character. (e.g. Japanese, Chinese, Korea)
• No need to keep open AUTO-KICK page to enable auto-kick script. This script is valid each page in WebAdmin.