Blurry/distorted text when downscaling from 4k to 1080p

[epsilonender]

I have been trying to record from a 4k monitor and downscale it to 1080p. But no matter how I played around with the output and video setting in OBS, the text in the recorded video is extremely blurry.

My settings are:

• Output
  
  • Output Mode: Simple
  • Recording Quality: Indistinguishable Quality, Large File Size
  • Encoder: NVENC HEVC
• Video
  
  • Base Resolution: 3840x2160
  • Output Resolution: 1920x1080

I tried to play around with different downscale filters, and it seems the "Area" filter gives the best result. But it is much worse when compared to videos recorded using other software (such as Nvidia ShadowPlay) with similar setting.


Below are some screenshots from the videos I got from OBS / ShadowPlay / Xbox Game Bar

Using OBS "Lanczos" Downscale Filter:

Using OBS "Area" Downscale Filter:

This one looks a little better than the Lanczos filter one, but some lines in the letters are rendered too thin (like the "E" in PAX East in the last line)

Using Nvidia ShadowPlay:

The output resolution is also downscaled to 1080p, but ShadowPlay gives a much much cleaner result

Using Windows 11's Xbox game bar:

Well, even the built-in recorder in Windows does a much better job than OBS...



...... so are there some ways that I can do to improve the text quality when recording with OBS?

Also, one of the weird thing I have noticed is that the videos recorded by OBS only use 2-3 Mbps bitrate (even when I manually set the bitrate to 50 Mbps), but the videos recorded by ShadowPlay/Xbox game bar use around 5 Mbps when I'm recording the same scene (a static webpage).


My OBS log: https://obsproject.com/logs/N351j00Q9W2aO6hB