When I do it, there is no (Windows) GUI. I ditched Windows 20 years ago. Since then my "desktop" (also laptops) is Linux. (Will add that to my profile.) Therefore, it goes like this:
# dd if=moodlebox-4.5.1.img of=/dev/mmcblk0 bs=4M && sync
My colleague has discovered the GUI program (on his Windows) though.
We two work at two different places and on different hardware; I have a 4 B 4G and a 3 A+, he has a couple of 3 B and 3 B+. I don't know what he sets for SSID etc. But the fact is he connects an Android smpart-phone and a PC with a USB wi-fi adapter to the MN. So the SSID/Password pair must be right.
Initially, he even claimed that SDs made with Windows (on the GUI above) work. At a closer look they didn't.
Then he made a new set of SDs and testing one. The test being connect the MB to a router, connect the client to MBs wi-fi and watch whether wireless signal fluctuates and/or it gets disconnected and reconnected, all the time while watching a YouTube video on the client.
Edit: Now comes to my mind, does the WPA standard setting of the client matter? There are all sorts of WPA2, WPA3 with additions like Personal, Extended, ,etc. Or put it another way, what is the correct setting for the WPA? You have no problems with MB v4.5.1, I assume.