Is it ok to switch the job from MNC to startup?

You will have trouble switching back... Startup comes with uncertainty and low WLB...

It’s ok

There you go with the validation you are looking from strangers. Bro, how can someone here even help you with zero details?

Totally depends on you. If you are a hustler and want to try some spice and exponential growth, then come to startup. If you like comfort and normal growth, you can continue with MNC. MNCs are process oriented and startup’s look for people who can break the process and get this things done. Process oriented vs Executor is the choice.