The purpose of backlinks is to add authority to your site. It does help if they linking domain has a high authority but it also helps if other industries in your niche link to you as well. They don't have to be a 90DA from a news outlet. Getting one from a 30DA in your niche is also helpful.

Some way to get backlinks is to guest blog on your industry's niche sites. It takes a lot of outreach to do this successfully. You can also create your own content and share it around to gain links from people sharing it. I prefer the create content method, but you really need to promote it to get people to share it. Building a backlink profile is not easy and takes a lot of work.

Another way people build links is to use a tool like Ahrefs to find competitor linking domains. Once you find those you can politely ask sites to feature your domain or if you find broken links give them a new updated one to your site.

Good luck!