I am excited to finish this game after so many years but cannot select Act V.

I attached a screenshot showing Act V still unlocked.

Cheers!

Well i figured out i can actually access it by clicking the V button.

Disregard lol, but man that confused me so hard.

Cheers!

Keep in mind that there's a final interlude available as well but this one you actually NEED to unlock. For this interlude to unlock (if it is not) you need to replay a bit from act 1:

Play act 1 until you get Weaver's adress.
Access the map but drive right back to Equus Oils.
Talk to the guy who is now there.

Now you can return to the circle and access the new and final interlude.