The regex that works with PCRE2 is the following:

<svg(?:\s+viewBox="(?<viewBox>[^"]+)"|\s+width="(?<width>[^"]+)"|\s+height="(?<height>[^"]+)"|\s+[^"]+="(?:[^"]+)")+>

Test string:

<svg fill-rule="evenodd" fill-rule="evenodd" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" fill-rule="evenodd" width="211" fill-rule="evenodd" height="61" fill-rule="evenodd">

regex101 link: https://regex101.com/r/Kje49r/1