Switch From Squarespace 7.0 to 7.1

Description

I need assistance transferring my website to Squarespace 7.1. I would appreciate honesty in the ability to complete the task before sending a proposal. I require someone experienced with previous transfers, as any error could cause significant harm to my business. I have also reached out to Squarespace developers via the Squarespace Developer Platform, so I will have a range of different quotes.
The website comprises approximately 300 pages.
1. I need a backup taken of the existing website.2. I have checked, and the current template is compatible with 7.1, so that is not an issue. Please recheck this to ensure there is no doubt.3. I need the existing website transferred over with all of the data, particularly the existing SEO for all pages, including internal linking and H1, H2, H3, paragraph headings, and titles, to avoid losing current page rankings or ending up with broken links.
I would like the job completed within a week.