Functional testing is my passion and I have done it for much greater clients. I have done testing for Microsoft, Facebook Inc (all platforms of Facebook and Insta;web and apps), Deezer, Deepop, Homelight and many others.
I have also been doing freelancing on Upwork and have done testing for video conference applications and adventurous puzzle games
If you require confidentiality regarding your identity or your app name, I can keep it secret to myself as some clients don't want their app/web name to be exposed.
I can provide more samples if you want to.