Your premise appears to be that praying to Our Lady is the same as worshiping some pagan deity. Putting aside the conflation of two entirely unrelated issues, I find your premise flawed.
For starters, I truly don't know how many Marian devotions I personally have prayed. I only converted to Catholicism relatively recently but I participated in a few Rosaries in my Anglican days. That along with Rosaries in which I've participated in my FSSP parish as well as my daily prayer routines which include Alma Redemptoris Mater and Hail Mary (or sometimes I substitute Angelus for Hail Mary but they're basically the same) means I've likely prayed at least 1,000 Marian devotions just in the last couple of years.
As far as trivia is concerned, nobody should be impressed with the 1,000 devotion figure. Assuming that's even accurate, there are people who easily double, triple or more that number. I'm not bragging. I'm setting the table.
All of this is to say that I have not experienced demonic oppression in my home or in my life. Now, I'm one person in one place at one time in history. If, as you say, prayers to Our Lady do somehow result in demonic attack of some sort, surely I'm a statistical fluke. And yet, I've never heard of any Catholic experiencing oppression with a Marian devotion.
Pope John Paul II apparently had a very strong Marian devotion. He was a famous public figure. You'd think he'd have made for an attractive target for demonic attack. And yet there are no credible reports of such a thing. I haven't even heard of an incredible report.
This is true of billions of Catholics through history. None of them are said to have suffered demonic attack due to any level of Marian devotion.
So right there your premise seems logically flawed. If asking Our Lady to pray for us is somehow inherently dangerous, well, at a minimum the "danger" as you've described it seems incredibly unlikely.
But more broadly, part of my Marian devotion is asking Our Lady to pray for me that I can resist certain sins that are unspeakably tempting for me. And this is where the rubber meets the road on my conception of Marian devotion. Because the sins I'm tempted by are, I would assume, the very sins the devil would want me to experience. I'll spare you the details because it's my cross and my burden and I share it only with whom I will. My point is that I'm tempted by sins the devil is especially famous for promoting.
My Marian devotion has helped me resist those temptations.
Ask yourself: Will the devil lift a finger to help me resist sin? Again, I should assume he probably won't. And yet I receive spiritual reinforcement to resist my sins anyway. Since the devil probably won't help me resist those sins, that leaves only one other source.
As an alternative explanation for my spiritual reinforcement, in theory it's possible that I'm lying to you. But, with all due respect to all members of CF, you're all a bunch of nameless, faceless strangers to me. I know nothing and care even less about your opinions of me. Putting morality aside (eg, I believe lying is a sin), it's not worth my time to lie to you. I can't be expected to lie to people for whose opinions I care nothing. Don't get me wrong, I'm happy that many people on this forum agree with me. But in the end I don't need and won't seek their approval. So why the heck would I bother telling fibs?
Another alternative is that it's all in my imagination. Perhaps I believe I'm being strengthened after my petitions to Our Lady. This is possible. But why would my temptation be reinforced by a practice about which I was initially skeptical? I said I'm Catholic but I never said I'm any good at it. In particular, I had to be convinced with my Marian devotion. Why would a devotional practice about which I was skeptical be psychologically effective in helping me resist my temptations?
Considering the abject lack of evidence (or even substantial rumors) as to the dangers of petitioning Our Lady combined with my own positive results, to me the shortest distance between two points is that there is no danger in Marian devotion. On the contrary, the practice has many positive spiritual benefits to it.
Having said that, I would assume nobody in this thread is dismissing the danger of necromancy, divination, summoning or other magicks. Those are obviously incredibly dangerous and should be avoided at all costs for all the obvious reasons.