can't open new tab in react, adds localhost:3000 on link?
try this
<Link target="_blank" to={"//www.mylink.com"} >mylink </Link>
or this
<a href={'//www.mylink.com'} target="_blank" > mylink </a>
for more reference:
Absolute vs relative URLs
https://en.wikipedia.org/wiki/Uniform_Resource_Identifier#Generic_syntax