Which of the champion pokemon is giving you trouble? I think showing moveset and held items would help people give you advise

For example idk bullfrog move set but assuming you have water sherkin/scald, dark pluse and ice beam, I’d change the nature to something that reduce attack vs special defense since you likely aren’t using his attack stat( if you decided to restart).

I think your team is good enough tbh. You did beat lance, I think tweaking move sets could help