Pobre com esperança

I would like to understand how these currency yield calculations work. I got #vgx when I was losing +20%, now the drop has decreased to 7 and the value is not growing.

I have the slight impression that this is all a huge mess.

If anyone knows how to explain it, please explain it to me.

Another question I also have is why every time we convert the total value is reduced even with a zero rate.