Wordpress export problem

I installed Ghost and I’m trying to export data from Wordpress with Ghost official plugin.

Wordpress is 5.6 and I converted categories to tag, I have about 2-3GB of data with images and articles, I have more than 400 articles.

I have 2gb of max ram usage in php and 6000 seconds in max execution time. After some time it exports a zero byte .zip file. It gives no error in network request and in console.

Maybe it’s a RAM problem?
Thank you.

EDIT: It’s not a RAM problem, it’s using about 5% of available memory.