Migrating Files for a new iMac

My 2012 iMac needs replacing and I want to simplify and clean up Duplicates, as well as continuing Error messages. Do I need to Format my new 1T G-Tech SSD before copying selected image and document files? I was hoping to copy them onto new iMac rather than use the Migration Assistant Software. My logic is that I don’t want to inherit issues, making a new start. I will then Erase the new SSD and establish it for my Time Machine Back-ups. I do have the Apple Time machine connected over WiFi but as it is no longer supported by Apple, I am trying to cover all options of reliable External Drives.

migrate time machine, the old machine is probably so far past its best before…

migration assistant is handy

  1. Open Migration Assistant, which is in the Utilities folder of your Applications folder. Then click Continue.
  2. When asked how you want to transfer your information, select the option to transfer from a Mac, Time Machine backup, or startup disk. Then click Continue.

As I stated in my Post, I am reluctant just to use Migration assistant due to the number of Error Login/Keychain Bug messages I am receiving, so therefore wanting to almost start from scratch avoiding File corruption, tidying my Filing and any Duplicates.
Whilst with the new iMac, I will then have full benefit of Apple Support for two years, I was hoping just to copy important Image/Video files as well as certain Documents. I will even Stop using Adobe Creative Cloud (Ending my account for Lightroom/Photoshop) as I am simplifying my retirement.
I was therefore asking if after the Files have successfully Copied, should I then Erase and re-Format the SSD in order to establish this Drive as a ‘Mac only’ Time Machine Back-up Drive? No doubt my Apple Wifi Time Capsule is about to expire!?