Is the devil using LGBTQ to destroy Christian churches?
Yes, and no.
First, the answer depends on how the word "churches" is defined because the Church, the ecclesia, are those called out by Christ as his body, the temple of God. However, the word is often used to mean any group of people claiming to be followers of Jesus. The two are not identical. The former, ecclesia, is not, will not, and cannot be destroyed. The latter can and will be destroyed. The former welcomes the LGBTQ as converts to Christ, calling them to obedience defined by God's word and empowered by God's Spirit. The latter is subject to the winds of any and every philosophy. Which brings me to my next point....
Second, I am much more inclined to blame sinful human flesh than the devil because the devil is a defeated enemy who is himself enslaved by sin to sin. In other words, just because some individual or group of individual espouses an aberrant and abhorrent position and calls others to join him in that belief does not mean it came from the devil. Humans are quite capable of lying all on their own. Sinful man does need the father of lies to lie, or any spiritual entity to come up with depravity or disobedience. Just because scripture states we don't wrestle with flesh and blood but with spiritual principalities does not mean that verse doesn't have defining context or hyperbolic import. Sin controls humanity just as much as it controls all devils.
Third, there were LGBTQs in the first century. There have always been what we now call "LGBTQ"s and God has always known of their existence. It's nothing new, not to God, not to Jesus, not to the ecclesia. What is new is the perversion of democratic principles. LGBTQ is a diversion compared to the corruption of democracies (parliaments and/or republics). In America, for example, we have a representative republic in which the views of the majority rule, but not at the expense of the rights of the minority. What we're seeing is a small percentage of Americans (a minority) usurping this principle and imposing their views on the majority. That is MUCH more devilish, insidious, depraved, and dangerous than the presence of LGBTQs in fake-Christian and true-Christian congregations. Do not be distracted.
Fourth, God is charge. He and He alone is sovereign and almighty, sovereignly almighty. NOTHING happens without either His doing or His consent and there is not a fraction of anything that happens that does not serve His purpose.
Therefore, the best play for those of the ecclesia is to believe Jesus and live right. The single best apologetic is a life well-lived. That means living, speaking and doing, as if we actually believe Jesus, not just believe in Jesus.