Additional reasons to suspect diabolical origin ...

"Revelation" claiming that this chaplet is the "last hope" for mankind ... uttered shortly after Our Lady of Fatima had told Sister Lucia the same thing about the Holy Rosary.

"Revelation" claiming encouraging people to say the chaplet during every free moment they have ... whereas Padre Pio said that about the Holy Rosary.

"Revelation" insisting that the chaplet be said on Rosary beads.

Between these 3, it's clearly an attempt to displace the Holy Rosary ... which the devil knows has extraordinary power in these days, per Our Lady's promises.

In addition, the devil has all but supplanted devotion to the Sacred Heart of Jesus with this new-agey-beam-of-light nonsense.

Now, Our Lady revealed the Holy Rosary not just so people could mutter words over and over again ... something which Our Lord actually condemned ... but because the repetition anchors part of the brain that then allows another part of the mind to be freed up toward mediatation and contemplation.  It's an amazing way to teach the faithful how to engage in mental prayer.  Now, the reason I believe Our Lady insisted upon 15 minutes of meditation on thy mysteries of the Holy Rosary as part of the First Saturday devotion is because many did likely develop a tendency just to mutter the words without actually using it as intended as an aid in meditation.

But given the timing, the clear intent to replace/supplant the Holy Rosary (contradicting Our Lady at Fatima), as well as the assertion about a light coming from Poland that's nearly always applied by Conciliars as some divine endorsement of Wojtyla ... I'm 90% certain that this devotion was diabolical in origin, and not just a reflection of Faustina's psychological problems.  Oh, and there were also those weird incidents that might be read as an endorsement of Communion in the Hand.

I beleive that the devil used various forms of flattery (unheard of in any genuine private revelation, which usually involves Our Lord HUMBLING the recipient of the revelation, lest the revelation fill them with pride) ... where Our Lord allegedly told Faustina the she was the greatest saint who ever lived and that Our Lord was sparing the entire world on account of her, etc. ... effectively putting her on a part with Our Lady.  If something appeared to me and told ME that, I'd instantly realize it was diabolical nonsense ... being a total load of BS.  But the devil knew that Faustina was inclined toward pride and would just "eat this stuff up" ... whereas anyone with even a modicuм of humility, even (and especially) the greatest of saints would immeidately dismiss this as diabolical deceit.  You also hear that despite being told by her confessors and fellow religious to ignore and dimiss these revelations since they were not genuince, she kept seeking "second opinions" until she got the one she wanted to hear ... from Fr. Spocko there.

This was the very part that convinced me Faustina was delusional, the way "Christ" just went on and on heaping praise on her. Not even Paula White is that shameless in boasting about her special relationship with the Almighty. I immediately wanted to stop reading because it was so disturbing.

Yeah, it was extreme to the point of being nauseating.  ANYONE with even the tiniest modicuм of humility would reject that nonsense and see it for the diabolical deception it was.  If some apparition of light appeared to me and told me that stuff, I'd laugh at its sulfer-stained hooves, telling it, "Surely with that angelic intellect you can do better than this."  But Faustina soaked it up ... and that was what made her into a tool for spreading this deception.

What worse, is that it totally degrades the purpose of Fatima.  Fatima included the purpose of amendment because the 5 first saturdays involve confession.  But Fatima's main message was OTHERS.  Pray for the souls in purgatory.  Pray and do sacrifices for sinners.  And...do PENANCE for sins.

Great point about praying for others ... and one that I hadn't noticed before but spot on, as it's totally absent from the DM message.  While Our Lady at Fatima showed the children Hell and pleased for them to sacrifice to save souls, DM almost makes it seem as though salvation is almost assured, and Our Lord's Mercy so superabundant that very few are condemned to Hell.

Sacred Heart of Jesus, I put my trust in Thee.  Saint Pius X 

Since the Divine Mercy chaplet is prayed on the Rosary beads, and is faster, it is largely replacing the recitation of the Rosary in the Novus Ordo.

I don't mean to be contrary, but having worked in agricultural research at a Land Grant University for 15 years (as a technician and dairy herdsman, not a scientist), I can't avoid the importance of precision and accuracy, (and citing verifiable sources), not that I'm always perfect in those traits.

I don't know much about the Divine Mercy devotion (I've always had a strong devotion to the Sacred Heart) and can't comment on what is said here about it.  I have no idea how long it might take to recite it.

I'm a registered parishioner in the Diocese of Spokane.  In semi-retirement I work part time for a funeral home, frequently assisting with funerals at neighboring parishes in the Diocese of Yakima (and I pick up a copy of their bulletins to read).  I routinely read the digital version of the Seattle Archdiocese newspaper.  I believe I can accurately say that the statement quoted above is absolutely untrue.  Some parish churches may have the Divine Mercy image (which I particularly don't care for), and some may (or may not) have had a procession and Holy Hour last Sunday (I was at a Ruthenian Divine Liturgy last Sunday).  However, of the parishes in a thirty-mile radius of the Tri-Cities in southeastern Washington (8, and there are reports that a new parish is going to be erected), almost all have a public recited Rosaries one or more times a week.  For the Vigil service the night before a funeral Mass, the Rosary is almost universally chosen by families, in lieu of or in addition to Vespers from the Office for the Dead, often followed by the Litany of Loreto.  Other than last Sunday, the Divine Mercy is NEVER mentioned.  So no, the chaplet is NOT replacing the recitation of the Rosary.

I don't know if this gentleman's youtube channel has been mentioned before but
he does some in depth videos on Polish messianism that formed the thinking of Faustina and JPII.

If the link doesn't work it's called Ascent of Mount Carmel

https://www.youtube.com/@ascentofmountcarmel438/videos

John Paul II couldn’t discern much when he helped Canonize St Faustina and promote Bergolio.