How is called this kind of "defect" and how to mitigate? (if possible)

[Selur]

Here's what that first idea does:

# converting interlaced to half-height progressive for filtering (vsMCTemporalDenoise) (separate fields)
clip = core.resize.Bicubic(clip=clip, format=vs.YUV444P8, range_s="limited")
clip = core.std.SeparateFields(clip, tff=False)
clipEven = clip[::2] # resolution 720x288
clipEven = core.std.SetFrameProps(clip=clipEven, _FieldBased=vs.FIELD_PROGRESSIVE) # progressive
clipOdd = clip[1::2] # resolution 720x288
clipOdd = core.std.SetFrameProps(clip=clipOdd, _FieldBased=vs.FIELD_PROGRESSIVE) # progressive
# denoising using MCTemporalDenoise
clipEven = denoise.MCTemporalDenoise(i=clipEven, settings="very high", ncpu=10)
# denoising using MCTemporalDenoise
clipOdd = denoise.MCTemporalDenoise(i=clipOdd, settings="very high", ncpu=10)
# converting half-height progressive to interlacedbefore deinterlacing
clip = core.std.Interleave([clipOdd, clipEven])
clip = core.std.DoubleWeave(clip=clip, tff=False)  # resolution 720x576
clip = core.std.SelectEvery(clip, 2, 0)
clip = core.std.SetFrameProps(clip=clip, _FieldBased=vs.FIELD_TOP) # tff
# Deinterlacing using TIVTC
clip = core.tivtc.TFM(clip=clip, chroma=True)
clip = core.tivtc.TDecimate(clip=clip, mode=7, rate=23.9760, dupThresh=0.04, vidThresh=3.50, sceneThresh=15.00)# new fps: 23.976
# Making sure content is preceived as frame based
clip = core.std.SetFrameProps(clip=clip, _FieldBased=vs.FIELD_PROGRESSIVE) # progressive
# applying anti aliasing using santiag
clip = antiAliasing.santiag(c=clip, strh=3, strv=3, nns=2, qual=2, pscrn=2, opencl=True)

clip

2nd idea: using SpotLess before the deinterlacing and BasicVSR++ on the edges after Santiag. (script,clip)
3rd idea: adding CodeFormer to before BasicVSR++ (script,clip)

Hope these help to get it started.

Cu Selur