Microsoft Edge (for Mac)
- Open Developer tools (option + command + i)
- Enter Device emulation (shift + command + m)
- Set Dimensions to Responsive and enter desired width and height
- Click the three dots (…) and choose Add device pixel ratio and change DPR to 3
- Press shift + command + p and type Capture Fullsize Screenshot
Bonus:
You can make it even more high res if you also change zoom level to 200%.