The line on the new certificate that goes like this seem unnecessarily convoluted :
1 of 6 freeCdeCamp certifications, representing approximately 300 hours of coursework
isn’t it a bit odd to put the number of certificates available on the new finished certificate like an ad? Probably that first part should go to instead highlight the 300 hours of coursework.
When I went to college, I’m sure there were hundreds of certificates available too, but on the certificate I earned it’s shown as just the one I passed, not how many were available 
As the number of certificates decreases or grows, it’s not a matter for the certificate to quantify. It’s about the person who earned it. They are your brand awareness ambassadors, not the certificate itself.
Let’s keep the focus on their achievement.
Cheers
EDIT: Also 1/6 in any context I’m sure can find a way to be taken out of context! Especially when HR is involved. They might think you’re not done yet, which undermines your achievement