To increase the DA value, or quality, of your domain name, you should do the following;
1 - Prepare quality content that will benefit the user.
2 - Write these contents in detail as H1 headings, H2 subheadings and H3 headings
3 - Create link outs, or link building, from the keywords in your content to your other content and external sources.
4 - Support your content with high-quality and authoritative backlinks.
5 - Regularly check for harmful backlinks and reject the ones you detect with Google disavow.
6 - Always do all these processes regularly and sustainably.
After a while, you will see that DA and PA values increase.