Can "volmaakt" not work in this context as an alternate to "perfect"?
Yes, I think that would be fine.
why does ongeveer not work, is there a specific context needed to use it?
Ongeveer can be more as well. It's used like the English "around":
Het is ongeveer 20 kilo - It's about 20 kilos.
Ik spreek Nederlands perfect ;)
dutch native here.
you ALMOST speak dutch perfectly
Does this mean playing a sport or instrument or like when a child is playing???
It can mean both.
Is there any distinction to note here in the use of bijna as opposed to altijd ?
Bijna means almost
Altijd means always
Is volstrekt admissible here?