Domain Migration After Losing a High-Ranking Domain – Best Practices?

**Hey, SEO folks!** I have a question regarding domain migration. A client of mine lost his long-established domain due to a domain dispute case in court. He was generating a significant number of leads through organic rankings, but the sudden suspension is now negatively impacting his business. I advised him to purchase a new domain using his business name since reactivating the suspended domain might take a long time—if it’s even possible at all. He has already purchased the new domain, and I’m now in the process of migrating the content from the old site. Should I publish all the content at once, or would it be better to release the pages in small batches? Additionally, if the old domain is reactivated, I plan to implement page-level 301 redirects to transfer the authority it has accumulated. In this case, should I keep the old domain and its sitemap in Google Search Console? If I keep both sites live, would it lead to duplicate content issues? TIA!