Needs["MaTeX`"]

Fqs[η_,x_,y_]:=(1/2)((x/((x^2)+(η^2)))+(y/((y^2)+(η^2))))
FSRG[s_,x_,y_]:=((x+y)/((x^2)+(y^2)))(1-Exp[-((x^2)+(y^2))s])

fig1=Grid[
{{With[{η=1},Plot3D[Fqs[η,x,y],{x,-5,5},{y,-5,5},Epilog->Text[MaTeX["f^\\text{qs$GW$}(x,y;\\eta) = \\frac{1}{2} \\left( \\frac{x}{x^2+\\eta^2} + \\frac{y}{y^2+\\eta^2} \\right)",FontSize->18],Offset[{30,-10},Scaled[{0,1}]],{-1,1.3}],
PlotPoints->100,MaxRecursion->2,ColorFunction->"DarkRainbow",PlotTheme->"Scientific",PerformanceGoal->"Quality",BoxStyle->Directive[Black,16,Thickness[0.005]],AxesStyle->Directive[Black,16,Thick],ImagePadding->{{5, 0}, {10,0}},PlotRange->{{-5,5},{-5,5},{-0.65,0.65}},Ticks->{Automatic,Automatic,None},AxesLabel->{MaTeX["x",FontSize->20],MaTeX["y",FontSize->20],None},BoxRatios->{1,1,2/3},ImageSize->400,BoxStyle->Thick,BaseStyle->Directive[16],ViewPoint->{0.65,-1.75,1.25},PlotStyle->Opacity[0.75]]],With[{η=1},Plot3D[FSRG[1/2(η^2),x,y],{x,-5,5},{y,-5,5},Epilog->Text[MaTeX["f^\\text{SRG-qs$GW$}(x,y;\\eta) = \\frac{x+y}{x^2+y^2} \\left[ 1 - e^{-(x^2+y^2)/(2\\eta^2)} \\right]",FontSize->18],Offset[{30,-10},Scaled[{0,1}]],{-0.9,1.3}],
PlotPoints->100,MaxRecursion->2,ColorFunction->"DarkRainbow",PlotTheme->"Scientific",PerformanceGoal->"Quality",BoxStyle->Directive[Black,16,Thickness[0.005]],AxesStyle->Directive[Black,16,Thick],ImagePadding->{{5, 0}, {10,0}},PlotRange->{{-5,5},{-5,5},{-0.65,0.65}},Ticks->{Automatic,Automatic,None},AxesLabel->{MaTeX["x",FontSize->20],MaTeX["y",FontSize->20],None},BoxRatios->{1,1,2/3},ImageSize->400,BoxStyle->Thick,BaseStyle->Directive[16],ViewPoint->{0.65,-1.75,1.25},PlotStyle->Opacity[0.75]]]
}},Spacings->0]

Export["~/fig1.pdf",fig1];