Given lots of the upstream for recycled pulp is explicitly coated in PFAS I assume all recycled paper products has PFAS contaminiation.
As of early this year the PFAS in food containers is being phased out, but that'll take a long time to catch up.
It's also really hard to tell what glues and inks were used, if the box was impregnated with poisons to keep rats out, etc.
I don't think it's worth the risk of poisoning the land when thick layers of leaves or local wood chips do at least as good a job.
https://www.mainepublic.org/2023-04-10/our-sewage-often-becomes-fertilizer-problem-is-its-tainted-with-pfas