Question: Solve and RootOf(allvalues)

I want to solve the problem described below. I tried using two methods as shown below, each method has been runing for days without solving it. I will really appreciate your help.

Det1 := (1/256)*(Aiso*(c+t)^2*(a^2+b^2)*(mu-1)*Pi^2-4*a^2*b^2*c*Gc)*(16*Aiso^2*Do^2*(c+t)^4*(a^2+b^2)^6*Pi^12+10*(a^2+b^2)^5*((c+t)^2*Aiso+4*Do)*Gc*(c+t)^2*c*a^2*Do*b^2*Aiso*Pi^10+(a^2+b^2)^4*((c+t)^2*Aiso+4*Do)^2*Gc^2*c^2*a^4*b^4*Pi^8-(1024/81)*a^6*Aiso^2*b^6*Tcr^2*(c+t)^4*(a^2+b^2)^2*Pi^4-(2560/81)*a^8*Aiso*b^8*c*Gc*Tcr^2*(c+t)^2*(a^2+b^2)*Pi^2-(1024/81)*a^10*b^10*c^2*Gc^2*Tcr^2)*(Aiso*(c+t)^2*(a^2+4*b^2)*(mu-1)*Pi^2-4*a^2*b^2*c*Gc)*(Aiso*(c+t)^2*(a^2+b^2)*(mu-1)*Pi^2-a^2*b^2*c*Gc)*(16*(c+t)^4*(a^2+(1/4)*b^2)^3*Do^2*(a^2+4*b^2)^3*Aiso^2*Pi^12+(10*(a^2+b^2))*((c+t)^2*Aiso+4*Do)*Gc*(c+t)^2*(a^2+(1/4)*b^2)^2*c*a^2*Do*(a^2+4*b^2)^2*b^2*Aiso*Pi^10+((c+t)^2*Aiso+4*Do)^2*Gc^2*(a^2+(1/4)*b^2)^2*c^2*a^4*(a^2+4*b^2)^2*b^4*Pi^8-(1024/81)*(c+t)^4*(a^2+(1/4)*b^2)*Tcr^2*a^6*(a^2+4*b^2)*b^6*Aiso^2*Pi^4-(2560/81)*a^8*Aiso*b^8*c*Gc*Tcr^2*(c+t)^2*(a^2+b^2)*Pi^2-(1024/81)*a^10*b^10*c^2*Gc^2*Tcr^2)*((mu-1)*(c+t)^2*(a^2+(1/4)*b^2)*Aiso*Pi^2-a^2*b^2*c*Gc)/(b^20*a^20*(c+t)^16) = 0;

# method 1;
EQN := RootOf(Det1, Tcr);

EQN_2 := allvalues(EQN);

# method 2;

EQN := solve(Det1, Tcr);