SEO. How to properly redirect an external link?

Question

JavaScript

On the site, almost every page has external links. How to make a redirect so that the search engines do not suspect anything?
Now it is done like this: using javascript, the link is processed,
http://google.comit turns into http://mysite.com/away/aHR0cDovL2dvb2dsZS5jb20=
Then the server makes a redirect
But this does not help to hide external links. Page analysis reports that the site has an external link. As I understand it, the robot reads the page before the script is executed.
It will be a little more difficult to remake links on the server, because the site uses a script for monetizing links (ad.fly), i.e. you cannot encrypt the link before it is processed by the ad.fly script. Due to the fact that you often have to make changes to this script, you don’t really want to do it on the server (recompilation, enabling options in the hosting panel).
rel nofollow and noindex are spelled out. But on the Internet, I read that it doesn’t really save, especially since the link will still be read, although it is not indexed.
So what is the right way to deal with external links? I read somewhere that search engines now recognize encrypted links as well.