How to print {ORDER TAGS} independently from {ORDERS}?

try this change.

[ORDERS]
A15,38,0,3,1,1,N,"{PRODUCT NAME}"
A15,68,0,3,1,1,N,"{ORDER TAGS}"

[ORDER TAGS]
* {ORDER TAG NAME}\n

That will resolve to

"*whipped cream\n
*extra espresso\n
*sub almond milk\n"

and I expect it to break \n to new lines.

if \n does not break to a new line you should find related EPL command to create a new line.