Debian 11.7 64bit- Kernel Linux 5.10.0-23-amd64 on x86_64
Run Arma 3 Server 64bit Vanilla with the command ./arma3server_x64 -port=2302 -name=server -cfg=Arma3.cfg -config=config_server.cfg -enableHT -filePatching -world=empty -nosplash -skipIntro -noSound -mod=""
Server starts running with normal cpu usage and waits for mission selection
After selecting a vanilla mp misson, sloting 1 player and hitting run, CPU usage goes to 160% to 300% and server becomes unplayable. Even the Ctrl+C takes too long to stop the Arma 3 server running.

server.cfg Configuration

steamProtocolMaxDataSize = 16384;
hostname = "My Server";
password = "123";
passwordAdmin = "mypass";
maxPlayers = 32;
persistent = 1;
forcedDifficulty="Custom";
admins[] = {""};
disableVoN = 1;
vonCodecQuality = 20;
voteMissionPlayers = 1;
voteThreshold = 0.33;
allowedVoteCmds[] =
{
{"admin", false, false},
{"kick", false, true, 0.51},
{"missions", false, false},
{"mission", false, false},
{"restart", false, false},
{"reassign", false, false}
};
motd[] ={"My Server"};
motdInterval = 2;
missionWhitelist[] = {};
timeStampFormat = "short";
serverRPTlocation = "/home/steam/arma3/logs";
logFile = "server_console.rpt";
BattlEye = 0;
verifySignatures = 0;
kickDuplicate = 1;
allowedFilePatching = 1;
battleyeLicense=0;
disconnectTimeout = 90;
allowedLoadFileExtensions[] = {"hpp","sqs","sqf","fsm","cpp","paa","txt","xml","inc","ext","sqm","ods","fxy","lip","csv","kb","bik","bikb","html","htm","biedi","b64"};
allowedPreprocessFileExtensions[] = {"hpp","sqs","sqf","fsm","cpp","paa","txt","xml","inc","ext","sqm","ods","fxy","lip","csv","kb","bik","bikb","html","htm","biedi","b64"};
allowedHTMLLoadExtensions[] = {"htm","html","php","xml","txt","sqf"};
onUserConnected = "";
onUserDisconnected = "";
onUnsignedData = "kick (_this select 0)";
onHackedData = "kick (_this select 0)";
onDifferentData = "";
doubleIdDetected = "";
localClient[] = {"127.0.0.1"};
headlessClients[] = {"127.0.0.1"};

Arma3.cfg configuration

language="English";
steamLanguage="";
adapter=-1;
Windowed=0;
3D_Performance=1;
MaxMsgSend=1024;
MinBandwidth=107374182;
MaxBandwidth=1073741824;
MaxSizeGuaranteed=958;
MaxSizeNonguaranteed=224;
MinErrorToSend=0.0020000001;
MinErrorToSendNear=0.02;
viewDistance=1000;
MaxCustomFileSize=0;

server.Arma3Profile configuration

version=1;
blood=1;
volumeCD=5;
volumeFX=5;
volumeSpeech=5;
singleVoice=0;
gamma=1;
brightness=1;
sceneComplexity=400000;
shadowZDistance=100;
viewDistance=1000;
preferredObjectViewDistance=800;
pipViewDistance=500;
terrainGrid=25;
difficulty="custom";
class DifficultyPresets
{
class CustomDifficulty
{

		class Options
		{
			reducedDamage=0;
			groupIndicators=0;
			friendlyTags=0;
			enemyTags=0;
			detectedMines=0;
			commands=0;
			waypoints=0;
			weaponInfo=1;
			stanceIndicator=1;
			staminaBar=1;
			weaponCrosshair=0;
			visionAid=0;
			thirdPersonView=0;
			cameraShake=1;
			scoreTable=0;
			deathMessages=0;
			vonID=0;
			mapContent=0;
			autoReport=0;
			multipleSaves=0;
		};
		aiLevelPreset=3;
		class CustomAILevel
		{
			skillAI=0.3;
			precisionAI=0.15;
		};

};
};