New User - I am a starting Dummy, with using powerful Ventoy

[GCMartin]

This utility has an Extremely attractive usefulness where I can boot this Boot Manager which presents ISOs it finds to user for selection. I have many questions for which the website is not geared for my ability to find answers.

So let me start by asking 3

1. Question #1: Does it matter if I use the Windows version created by Rufus or the Linux version to make the bootable USB?
   
2. I currently have created a folder on the 1st partition named "boot-isos" and placed my preferred ISOs within the folder for selection. This works as at boot time, I see the ISOs Ventoy found withing the "boot-isos" folder. Question #2: If I want to move this folder to my main system HDD, what must be done so that Ventoy will find the ISOs there?
   
3. One of my PCs is a modern 2016 vintage all in one PC. In its UEFI, Secure Boot is disabled. At boot-time, via the PC's boot device selector, I can boot the USB via the UEFI section or the Legacy section. But, for several of the ISOs, selecting and booting them gives VERY different results. Question #3: Is this something to do with Ventoy being booted from UEFI/Legacy OR is this something to do with the ISO itself?
   

These question may have been already addressed, but I am new and guidance is requested, please.