fixed width and height of svg objects - object

Question

I want to keep my polygon circle and path width same width and height on all devices for example 50px height and 50px width, because they are streched on mobile devices, or if there is another solution.
i deleted some css classes and other svg objects so code can be seen as simple.
<svg preserveAspectRatio="none" id="Layer_1" data-name="Layer 1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 734 414">
<g id="bg">
<rect class="cls-1" x="-0.01" y="0.96" width="733.99" height="92.47" />
<g id="bg_elements">
<path class="cls-2" d="M734,414H0V81.84s56,2.53,74.56,2.73c22,.23,64.67-3,86.71-2.86,24.83.18,109.22,6.38,136.17,7.46,45.2,1.8,105-5.57,149.73-7.27,39.45-1.51,118.14,3.66,157.5,3.66,32.42,0,129.33-5.29,129.33-5.29Z" />
<g id="elements">
<polygon id="triangle" class="cls-3" points="32.27 247.14 23.13 224.36 7.97 243.67 32.27 247.14" />
<circle id="ellipse" class="cls-4" cx="317.06" cy="160.33" r="12.53" />
<polygon id="triangle_s" class="cls-5" points="460.08 371.37 448.65 376.05 438.89 383.61 440.56 371.37 438.89 359.14 448.65 366.7 460.08 371.37" />
<path id="plus" class="cls-6" d="M651.11,227l-13.62,21.69m-4-
17.66,21.7,13.63" />
</g>
</g>
</g>
</svg>

Answer 1

If the svg has the viewBox and preserveAspectRatio all set, another place possibility is to use a container div and font-size something like:
<div style="height: 50px; width: 50px; fontSize: 50px">
<svg>...</svg>
</div>

Answer 2

Your requirements are not clear. But perhaps what you want, is for the SVG to cover the whole of the viewport whilst still staying unstretched/unsquashed. Ie. the equivalent of background-size: cover for HTML elements.
If that is the case, then what you want is:
preserveAspectRatio="xMidYMid slice"
This will size the SVG up or down so that it is the minimum size that still entirely covers the whole of the viewport. However you may end up with some parts of the SVG getting clipped off the edges.
svg {
width: 400px;
height: 300px;
}
path {
fill: red;
}
circle {
fill: blue;
}
polygon {
fill: yellow;
}
<svg preserveAspectRatio="xMidYMid slice" viewBox="0 0 734 414">
<g id="bg">
<rect class="cls-1" x="-0.01" y="0.96" width="733.99" height="92.47" />
<g id="bg_elements">
<path class="cls-2" d="M734,414H0V81.84s56,2.53,74.56,2.73c22,.23,64.67-3,86.71-2.86,24.83.18,109.22,6.38,136.17,7.46,45.2,1.8,105-5.57,149.73-7.27,39.45-1.51,118.14,3.66,157.5,3.66,32.42,0,129.33-5.29,129.33-5.29Z" />
<g id="elements">
<polygon id="triangle" class="cls-3" points="32.27 247.14 23.13 224.36 7.97 243.67 32.27 247.14" />
<circle id="ellipse" class="cls-4" cx="317.06" cy="160.33" r="12.53" />
<polygon id="triangle_s" class="cls-5" points="460.08 371.37 448.65 376.05 438.89 383.61 440.56 371.37 438.89 359.14 448.65 366.7 460.08 371.37" />
<path id="plus" class="cls-6" d="M651.11,227l-13.62,21.69m-4-
17.66,21.7,13.63" />
</g>
</g>
</g>
</svg>