That's one of those questions we've all asked ourselves, the truth is, yes, SMM panels for Instagram boost have stopped working as they used to, the problem isn't the panel itself, but rather that Meta has become very strict with inflated metrics.
These panels buy fake interactions, and instagram's algorithm is now very good at detecting them, when the system sees a sudden spike in followers or likes, but those accounts aren't real and don't interact with your content, you get a shadowban, this means your content stops appearing in your followers' feeds and on the Explore page, and your organic reach plummets.
Most of these cheap services use bots or fake accounts that disappear after a short time, leaving your account worse off than before, it's also common for them to block features like commenting or following people because the algorithm interprets it as spam, the only way it works is if you buy high quality interactions, which are more expensive, but most panels don't offer them.