play singles in a flex league and maybe tournaments if you are so inclined. Play doubles on your regular 4.0 team. It will help your singles game and eventually you may even like it.
I started out playing only singles. My first season of USTA league play, I got bumped to a 4.5B because my team went to playoffs. I was way overmatched at 4.5 league singles and I was a subpar doubles player (even for 4.0) so I ended up not playing much at the next season. So I started playing a lot more doubles in practice. Now that I am getting older I hardly play any singles any more.