The CooldownSoundPlayer Plugin has an error in the CooldownSoundPlayerPlugin.cs file on line 53,
replace:
if (EnableOnlyWhenIngameSoundIsEnabled &&! Hud.Game.IsIngameSoundEnabled) return;
per
if (EnableOnlyWhenIngameSoundIsEnabled &&! Hud.Sound.IsIngameSoundEnabled) return;
as described in the changelog:
BREAKING CHANGE: Hud.Game.IsIngameSoundEnabled is moved to Hud.Sound.IsIngameSoundEnabled