Just create a Pretty Links link that redirects to your Linktree URL.
For example, I created one called menu, which looks like this if I pass it around:
Click on that, it’ll take you to Wordpreneur’s Linktree page. Domain branding problem solved!
(Yeah, the visitor will see the Linktree URL in their address bar when they get there. So what? The link you’re passing around still has your brand.)