Isolate the last slide containing the white space.
Determine what is missing, in this case 2 Cards.
2 Cards width is 300% card width.
Make a internal gride wrapper on the last slide.
Put card in order of loop in the 2 slots.
To answer your question about loading performance, this solution does not impact loading performance in any way. Except for adding a few extra lines of code to CSS for new combo and grid class to make slider work the way you want it.
For mobile version, it will have minimal impact, perhaps set Overflow Hide and Max Width = 100% container for mobile as an option if you want to mask the other extended whitespace cards from last card transition.
to all other users reading this:
You can remove whitespce on your carosel to make it infinite coursel style with making “LAST SLIDE CLASS” span the width of white space, and using Grid to fill in the missing cards IN the Order you want them to appear, to make it stretch to the end to show all slides without missing whitespace
Here is resolution to left slide:
Including problem solving steps.