Can remove content from Google Search and create a new site with the same content?

Hey, everybody! Like many others, I suffered from Google's December spam update, and now 15 of my sites have 0 clicks and 0 impressions. I started to recover my sites. I bought a new domain, uploaded a backup, slightly changed the site, and rewrote the content. One site is already regaining clicks, but the process is slow. Two questions: 1. Can I create a request in Search Console on one of my sites to remove content and then upload a backup of that site on a new domain? I think Google should index the pages and not say they are duplicates. I saw that my competitor did that. 2. The removal request says it may take up to 6 months. Is that accurate, or does it typically happen faster?