Call Stack and Error Messages -- Unable to Change PHP Version

I’m new to Local, but have searched these forums for my answer to no avail. I found that upon loading my site, I got lots of ugly chart warnings / call stack info. The answer I found here is that I need to downgrade to an older PHP version so it doesn’t do this. There’s nowhere in the software (preferences, site setup, etc.) that allows for this. I read on, and saw you must create a “custom” environment, so I did this as a test.

With prefs set to default to a custom environment, I created a new test site – no options anywhere I could find to change PHP version – whether right click or elsewhere.

Everything else works great, but this is really frustrating and confusing. Here are a couple other screenshots I took: