Should I just quit or keep going?

Hey guys, A little backstory first, I'm hired as a Software Engineer by this start up company around March of 2021. I've working there till this day, and I can say that it's pretty tough. Not trying to down myself but just being honest, I realised that I'm really unqualified for this job. First thing is I thought the job is backend dev only but as it turnouts it's a fullstack dev, I did managed to learned abit of the front end part after a while. Second is, I'm not very familiar with the tools they are using but I'm too naive at that time to know how little I know. But my main concern is the very "strict" code review. It happens only a few times but basically the gist is whenever my code got rejected, my Senior will say something along the line of "add more of this (mostly test cases) , then it will be all good". But after doing what they ask, my code will be rejected again for entirely different reason. And just to add process from first request to second is not instantaneous, most of the time it will take a 2 to 3 days for it to be reviewed again. I know I'm not the best coder out there thats why I'm very glad whenever I get a feedback from my code. But after a while, it starts to wear me down. Not only the feeling of being rejected, but also the feeling that you think you've done your task after doing what you've been told but in the end you're back to zero again. I know code reviewing is hard, sometimes some ideas will sink in after a while. Also to add up this is a start up company and this Sr/Sr's are pretty overloaded. But I'm tired of repeating the same cycle over and over again. I've been thinking to quit my job and programming altogether. So what do you guys think. Any opinion will be helpful. Thanks.

TLDR: Thinking of quitting my job and the industry after my Senior keep rejecting my work for different reason each time.

I know noone will read this but mehh. Also apologies for the terrible English.