Redirect with get parameters in target url

Howdy, I’ve tried searching on this question, and everything I’ve found about this is going in the opposite direction as I need (get parameters to a dynamic url, I need to go from basic url to a url with get parameters).

I am trying to set up a redirection that will take a url like:
mydomain.com/landing3
to another page and add some get parameters:
mydomain.com/start-here?param1=const&param2=otherconstant_value

Unfortunately, when the plugin does the redirection, it is re-writing the target URL with the “&” url encoded:
mydomain.com/start-here?param1=const#038;param2=otherconstant_value

I need the & to be an ampersand, or else the needed data doesn’t get to the page in question/is ignored/stripped away by the app on the start-here page.

I tried escaping the & as \& but it is still appearing as #038; in the URL.

For now, I’ve use .htaccess to achieve this goal, but is it possible with this tool? I’d much prefer to keep the marketing redirections in this tool vs the .htaccess file.