Why is my animation so slow can someone help me ?

Hello I added some new things to my code, after this my programs runs very slow.

function [sys,x0,str,ts,simStateCompliance] = Berechnung(t,x,u,flag,P)

switch flag,
    
  
    case 0,
        [sys,x0,str,ts,simStateCompliance]=mdlInitializeSizes(P);
        
  
    case 1,
        sys=mdlDerivatives(t,x,u,P);
        
  
    case 2,
        sys=mdlUpdate(t,x,u);
        

    case 3,
        sys=mdlOutputs(t,x,u,P);
        

    case 4,
        sys=mdlGetTimeOfNextVarHit(t,x,u);
        
   
    case 9,
        sys=mdlTerminate(t,x,u);
        
        
    otherwise
        DAStudio.error('Simulink:blocks:unhandledFlag', num2str(flag));
        
end

function [sys,x0,str,ts,simStateCompliance]=mdlInitializeSizes(P)


sizes = simsizes;

sizes.NumContStates  = 2;
sizes.NumDiscStates  = 0;
sizes.NumOutputs     = 2;
sizes.NumInputs      = 2;
sizes.DirFeedthrough = 0;
sizes.NumSampleTimes = 1;   

sys = simsizes(sizes);



x0  = [0; 0];


str = [];


ts  = [0 0];

simStateCompliance = 'UnknownSimState';


function sys=mdlDerivatives(t,x,u,P)
h1        = x(1);
h2        = x(2);

ventilst     = u(1);
pumpe      = u(2);

v1 = P.v1_max*pumpe;

if h1 < 0
   h1 = 0;
end
if h2 < 0
   h2 = 0;
end


h1_dot = .1*((1-ventilst) * P.C1*v1 - P.C2*h1);
h2_dot = .1*-((1-ventilst) * P.C1*v1 - P.C2*h1);

if h1>=P.hT/1.4 && h1_dot>=0
    h1_dot = 0;
end

if h1>=P.hT/1.4
    h2_dot =0;
end

if ventilst== 1 && h1>=0
    h1_dot = -1;
end
if ventilst== 1 && h1>=0
    h2_dot = 1;
end
if ventilst== 1 && h1==0
    h1_dot = 0;
    h2_dot = 0;
end
if ventilst== 1
    %Weißer Hintergrund
    xbodenw1 = [-710 -710 -300 -300];
    ybodenw1 = [-50 50 50 -50];
    fill(xbodenw1,ybodenw1,'white','EdgeColor','white');
    fill(xbodenw1,ybodenw1,'white','EdgeColor','white'); 
plot([-710 -710], [0 60], 'black');
      %Knopf
    plot([-450 -400], [-50 -50], 'k');
    plot([-400 -400], [-50 -10], 'k');
    plot([-450 -400], [-10 -10], 'k');
    plot([-420 -430], [-50 -10], 'k');
    %Feder11
    plot([-650 -670], [-50 -25], 'black');
    plot([-670 -690], [-25 -50], 'black');
    plot([-690 -710], [-50 -25], 'black');
    %RECHTECK BENTIL
    plot([-550 -450], [50 50], 'k');
    plot([-450 -450], [50 -50], 'k');
    plot([-450 -550], [-50 -50], 'k');
    plot([-550 -550], [-50 50], 'k');
    %2
    plot([-550 -650], [50 50], 'k');
    plot([-650 -650], [50 -50], 'k');
    plot([-650 -550], [-50 -50], 'k');
    plot([-550 -550], [-50 50], 'k');
%Pfeil im Ventil
     plot([-500 -500], [-50 50], 'black');
     
    plot([-500 -490], [-50 -30], 'black');
    plot([-500 -510], [-50 -30], 'black');
%Striche

     plot([-600 -600], [49 24], 'black');
      plot([-620 -580], [24 24], 'black');
      
      plot([-600 -600], [-49 -24], 'black');
      plot([-620 -580], [-24 -24], 'black');

end
if ventilst== 0
     %Weißer Hintergrund
    xbodenw2 = [-710 -710 -300 -300];
    ybodenw2 = [-50 50 50 -50];
    fill(xbodenw2,ybodenw2,'white','EdgeColor','white');
    fill(xbodenw2,ybodenw2,'white','EdgeColor','white');
          plot([-710 -710], [0 60], 'black');

      %Knopf
    plot([-350 -300], [-50 -50], 'k');
    plot([-300 -300], [-50 -10], 'k');
    plot([-350 -300], [-10 -10], 'k');
    plot([-320 -330], [-50 -10], 'k');
    %Feder11
    plot([-550 -570], [-50 -25], 'black');
    plot([-570 -590], [-25 -50], 'black');
    plot([-590 -610], [-50 -25], 'black');
    %RECHTECK BENTIL
    plot([-450 -350], [50 50], 'k');
    plot([-350 -350], [50 -50], 'k');
    plot([-350 -450], [-50 -50], 'k');
    plot([-450 -450], [-50 50], 'k');
    %2
    plot([-450 -550], [50 50], 'k');
    plot([-550 -550], [50 -50], 'k');
    plot([-550 -450], [-50 -50], 'k');
    plot([-450 -450], [-50 50], 'k');
%Pfeil im Ventil
     plot([-400 -400], [-50 50], 'black');
     
    plot([-400 -390], [-50 -30], 'black');
    plot([-400 -410], [-50 -30], 'black');
%Striche

     plot([-500 -500], [49 24], 'black');
      plot([-520 -480], [24 24], 'black');
      
      plot([-500 -500], [-49 -24], 'black');
      plot([-520 -480], [-24 -24], 'black');
    end
sys = [h1_dot; h2_dot];




function sys=mdlUpdate(t,x,u)

sys = [];


function sys=mdlOutputs(t,x,u,P)
h1        = x(1);
h2        = x(2);

sys = [h1;h2];


function sys=mdlGetTimeOfNextVarHit(t,x,u)

sampleTime = 1;   
sys = t + sampleTime;

function sys=mdlTerminate(t,x,u)

sys = [];

[Walter Roberson]

One thing I would suggest would be to reduce the number of plot() calls.

plot([x11 x12], [y11 y12], 'black')
plot([x21 x22], [y21 y22], 'black')

can be drawn by

plot([x11 x12 nan x21 x22], [y11 y12 nan y21 y22], 'black')

which reduces the number of plot objects.

I notice that you do not have any "hold on" or "hold off". Either only the very last thing would be drawn, or else you have "hold on" somewhere else outside of this, in which case you have the problem that every time the function is called that you are plotting additional objects on top of what you have already drawn.