Forget practicing the tech for now. Sure it might be where you "fail" but it Sounds like performance anxiety is what is holding you back; work on your confidence in interview settings. Apply for jobs you'd never take (I mean, non tech jobs where you are sure to get an interview) to give you more practice in these settings.
I see this sort of thing in newer engineers we interview. It's the thing that makes it hard to get to the root of how good someone is.
Right now the sort of challenges the big 4 are setting might not suit you. You might need more experience elsewhere; that's okay, you've got a year as a SE, wirh some good previous background: the future looks bright. It does take a while to get there. I measure myself as successful; at 29 I am a well paid engineering team manager at a largish firm. We do cool tech and I get to promote Devops. 8 years ago I was on a cruddy wage doing very little engineering - but learned loads that set me up for success. Focus on what you can learn right now to make yourself better, add things in increments, don't burn yourself out looking for the shortcut. Most of all don't fall for the hype; there is so much more than the big 4 or a start-up, and they do good engineering too!
I see this sort of thing in newer engineers we interview. It's the thing that makes it hard to get to the root of how good someone is.
Right now the sort of challenges the big 4 are setting might not suit you. You might need more experience elsewhere; that's okay, you've got a year as a SE, wirh some good previous background: the future looks bright. It does take a while to get there. I measure myself as successful; at 29 I am a well paid engineering team manager at a largish firm. We do cool tech and I get to promote Devops. 8 years ago I was on a cruddy wage doing very little engineering - but learned loads that set me up for success. Focus on what you can learn right now to make yourself better, add things in increments, don't burn yourself out looking for the shortcut. Most of all don't fall for the hype; there is so much more than the big 4 or a start-up, and they do good engineering too!