>Edge stays in memory after we close the application. This is a known issue since it was released. However, it causes some performance issue. The fact that it keeps processing various operations after being closed affects the good running of the Windows session after. Despite having seen a lot of discussions on the topic and people requesting solutions to workaround that, I thought I would see if there would be a way to change something in the Registry or elsewhere that would forbid Edge to remain in memory. I always have to go in Task Manager and kill the process. After a while, this does not suffice. I have to restart Windows.
>
>Using IE works but it is slower. So, for now, I use a mix of both, based on the needs.

PowerShell has a number of HTTP-related functions. Depending on what you're doing, it might be an alternative to using a full browser e.g. Google [powershell interact with webpage]

My guess is PowerShell would not exhibit any "preloading" or "optimization" behaviours you might get with full-fat browsers.

As a side note, Microsoft Edge will soon be based on Chromium i.e. the same underlying engine as the Google Chrome web browser. I don't know if that will make its behaviour and resource consumption better or worse.