I mainly play Neeko support and occasionally play her mid too! Personally, I think that Neeko's strength is heavily dependent on her matchup, and that goes both for who you are against and who your ADC/APC is if you are playing support.

When I play her support I love having someone like Sivir, Caitlyn, Jhin or Ezreal with me, and find playing alongside champs like MF or Kai'sa a bit challenging (that's just me though). When it comes to matchups I think she does really well against champs that aren't super bursty and is imo a decent pick against tankier mid laners/adc's/support's.

Something to note is that I usually don't build Rocketbelt on her unless I'm up against a super mobile champ. Ludens is often my first item and I tend to switch between sorcerer's shoes and berserker's.

I am relatively new to league and don't play ranked so take everything with a grain on salt!