How much space does a 220V AC input power supply save compared to a 120V one?

For a given output voltage & current, how much space is saved by using 220V instead of 120V input?

Specifically, I want to know is it expected for 220V only welders to be much smaller than equivalent ones that have to work with both 120V & 220V. Here's a comparison. It's not exactly fair because the 220V machine has less cooling and only allows 25% duty cycle. Another comparison I could've done is compare a 220V only computer power supply vs a 120V one, but it appears there are no 220V only PSUs.

1. 
   

   220V: Bossweld 200 Amp TS200 (25% duty cycle @ 200A)

   
   
   
   
   
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     145mm x 280mm x 410mm = 16.6L

     
     
   
   
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     7kg

     
     
   
   
   
   

https://www.bunnings.com.au/bossweld-200-amp-ts200-tig-stick-inverter-welder_p6380047

2. 
   

   120V: Weldpro ACDC 200GD AC/DC 200 Amp, 40% duty cycle @ 200A

   
   
   
   
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     447mm x 201mm x 406mm = 36.5L

     
     
   
   
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     < 27kg

     
     
     
   
   
   
   

https://www.amazon.com/Weldpro-Digital-Voltage-welding-machine/dp/B07LCSXYN5

So the 120V machine is 2.2x bigger.

Assuming a welding power supply uses the same design as a computer power supply like described here and here.

Then it's obvious a 220V supply would only use 0.55 the current in all stages before and up to the primary coil of the transformer. Everything after that would be the same for both 120V and 220V.

So is it fair to conclude that the high voltage, non isolated side will be 1.8x bigger in a 120V design? What fraction is taken up by the other isolated, low voltage side?

I'm also assuming having to support variable input voltage shouldn't cost anything extra, because you don't need any extra hardware, just a different duty cycle.