Went through Forlorn streets followed by Desert Arena. Stopped proceeding any further at the time of writing this post.
New modifiers from Forlorn streets lasts for 2 echoes.
New modifiers from Desert Arena lasts for 3 echoes.
My current remaining modifiers:
2 echoes left of enemy modifiers.
1 echo left of player modifiers.
Assuming Desert Arena modifiers activates upon entering the echo, there should at least be 2 echoes left for player modifiers after completion of Desert Arena.
It doesn’t add up.