Hope you guys are doing great.

Here is something I found today.

Chrome extension to test the responsive design easily, with the full ability to debug the code using Developer tools.

check this out. It's totally free of cost.
Note: I am not the sponsor of this extension :)

https://chrome.google.com/webstore/detail/mobileresponsive-web-desi/elmekokodcohlommfikpmojheggnbelo

I hope this helps someone. have a great day