Never got any appreciation

I work at a very early stage startup (8months old). I joined in initial days as a fresher, since then I have worked really hard to build multiple systems from scratch.

One co founder is very biased against 2-3 people including me (all 2024 grads).

He has high expectations from us and we always deliver but now I feel like I am a labour...most of work comes to 3 of us.

He has hired his friend (no background of data science) and made him data team lead. It all feels so bad that you work is not being appreciated.

He never appreciates us instead find small mistakes and scolds on those issues.