Moving a custom domain blogger to wordpress is only possible on a self hosted wordpress
Blogger always allow any domain name registered by a 3rd party. U.S. based users can also use a domain registered with Google Domains.
You were asked to add CNAME and records to your domain’s DNS records, When you first setup the domain pointing to your Blogger blog. You will need to delete those records and add your WordPress host’s DNS settings.
You can get DNS settings required by your WordPress hosting provider from their support websites:
On the DNS Zone File page, you need to locate the A record and CNAME aliases you added for your Blogger blog and delete them. Click on save changes button to apply your changes.
The next step is to setup nameservers for your WordPress hosting provider. Go back to manage DNS page for your domain and then click on manage under the namservers section.
On the next page you need to click on custom and then click on edit nameservers link to add your new WordPress hosts nameservers.
Click on the save button to make your DNS changes go live.
Also, your Bloggger blog’s original blogspot.com address is redirecting users to your custom domain. Since we have changed the domain settings, we need to remove this from Blogger too.
Simply log into your Blogger account and go to Settings » Basic page. Under the publishing section, click on the cross icon to cancel the redirect.
If your domain’s DNS has gone live, you can then install WordPress on your hosting provider. If your domain is registered on a 3rd party service other than your web host, then you will need to add the hosting for the domain. After adding domain to your new host, the next step is to install WordPress.
After successful installation of WordPress on your custom domain, you will then import content from your Blogger blog.
Before you can import content into WordPress, first you need to export it from your Blogger blog.
Blogger allows you to export content in an XML file.
Login to your Blogger blog and click on Settings » Other page. Under the blog tools, click on the Export Blog link
This will bring up a popup where you need to click on the Download Blog button. Once that is done, it is time to import it into your WordPress site.
Importing to Wordpress
Login to your WordPress admin area and on your dashboard, go to Tools » Import page. There you will see a list of importers for different services. You need to click on Blogger to install the Blogger importer.
This will bring up a popup where you need to click on the Insall button. WordPress will now download and install the Blogger Importer plugin for you. Once it is finished installing the plugin, you need to click on Activate Plugin and Run Importer link to continue.
On the Import Blogger screen, WordPress will ask you to upload the XML file. Simply click on choose file button and upload the XML file you downloaded earlier. Click on the Upload file and import button to continue.
WordPress will now import your blogger posts from blogger, once it is finished you will be asked to assign an author to the imported posts. You can assign your blogger posts to an existing author or create a new one.
Congratulations! you have successfully imported your Blogger blog into WordPress. However, you still need to make sure that you don’t loose any search rankings and that visitors to your old blog can easily land to the same content on your new WordPress powered website.