Save as .ini in Documents\Rainmeter\Skins\BigSur\clock.ini , then refresh Rainmeter. Start with macOS Big Sur Rainmeter Suite from deviantART, then swap individual skins if needed. Combine with RoundedTB and TranslucentTB – that’s 90% of the look in under 20 minutes.
[MeasureTime] Measure=Time Format=%H:%M
[MeasureDate] Measure=Time Format=%A, %B %d big sur rainmeter
[MeterDate] Meter=String MeasureName=MeasureDate FontFace=SF Pro Text FontSize=16 FontColor=200,200,200,255 SolidColor=0,0,0,1 X=10 Y=70 Save as
[MeterTime] Meter=String MeasureName=MeasureTime FontFace=SF Pro Display FontSize=48 FontColor=255,255,255,255 SolidColor=0,0,0,1 AntiAlias=1 X=10 Y=10 Save as .ini in Documents\Rainmeter\Skins\BigSur\clock.ini