Just a remark to always benchmark your code to make this statement. As newer releases of .Net Core also Regex gets faster and faster.
So better stay maintainable and readable and let the performance guys do their work
References:

• https://devblogs.microsoft.com/dotnet/regex-performance-improvements-in-net-5/
• https://devblogs.microsoft.com/dotnet/regular-expression-improvements-in-dotnet-7/
• https://devblogs.microsoft.com/dotnet/performance-improvements-in-net-8/#searchvalues which is/will be used by Regex under the hood

Elegant one, but I persannoly chose not to use regex because it is rather slow in general.