[HELP] Ringing, Mosquito or Blocking

[lastchance22]

Hi everyone,
I’m having trouble improving the quality of an anime video and I can’t seem to fully fix it.
Source info:

• FPS: 29.970
  
• I already processed it with SRestore to get back to 23.976 fps
  
• I also used QTGMC to fix interlacing
  

Current issue:
There are still a lot of small bright and colored pixels around the lineart (edges). It looks like strong compression artifacts (ringing / mosquito noise), almost like an over-compressed JPEG.
What I already tried in Hybrid:

• DeHaloAlpha (Radius 2, Strength 1–2)
  
• HQDeRing (Y + U + V checked)
  
• Deband (f3kdb Neo, light settings)
  

Despite this, the pixels around the lines are still very visible.
What I’m looking for:

• Best way to reduce/remove these artifacts without destroying line detail
  
• Recommended filters or settings in Hybrid / VapourSynth
  
• Whether this can be properly fixed or if it’s just a limitation of the source
  

If needed, I can provide screenshots or a sample.
Thanks a lot for your help!