You could add a 301 redirect, so that the URL works, but the end URL will still be Webflow’s asset URL.
You could setup a reverse proxy which would give you exactly the URL you want, but adds a fair bit of infrastructure. I do a lot of work in this space.
You could also host the file somewhere else like bunny.net, and use a subdomain, like files.mydomain.com/myfile.
*You need a web server to host your website and handle requests. If you don’t have one already, you can use services like Apache, Nginx, or even a cloud hosting provider like AWS, Google Cloud, or Microsoft Azure.
Configure Web Server: Once you have your web server set up, you need to configure it to handle requests for your custom URL (https://psxcosmicvalues.com/) and serve the PDF file from the asset library when someone accesses mydomain.com/myfile