If you don't have Web Hosting, you have two options for connecting your domain with your Blogspot account.
You can use forwarding, which you are already doing or you can set up a custom domain and use a CNAME.
To use a CNAME, first, you'd need to follow Bloggers steps for creating a custom domain. Once you do that, follow these steps to create your CNAME:
How do I create a CNAME?
A CNAME record is short-hand for Canonical Name record, which allows you to assign a domain or subdomain to another address or hostname. CNAME records should only be used if you can't use an A record.
NOTE: If you already have an A record within the Domain records section, please SKIP step 5!
Select "My Domains" from the left-side menu bar and click "Manage Domains" in the drop-down.
Check the box next to the domain name(s) and select "DNS Settings" from the "Action" drop-down menu.
On the new page, select the "Dynadot DNS" option from the drop-down menu.
In the "Domain Record (optional)" section at the top, select "Forward" as the record type, choose forward type, and enter "https://www.yourdomainname.ext" as the "Target Host". (NOTE: This is optional and please replace the value based on your own domain name.)
Under the "Subdomain Record (optional)" field, enter "www" as the subdomain, select "CNAME" as the record type and enter the CNAME record given to you.
Scroll down to the bottom of the page and click on the "Save Settings" button to save your changes.