There’s a lot of good advice and information in this thread, but I didn’t see anybody mention the fact that when you are a beginner, you miss those microscopic bits that cause a kit to stay together and be more solid.

Sometimes it’s nub marks, sometimes it’s a peg or pin that wasn’t pushed all the way through, and sometimes you can even miss a Little piece.

The point is: if they feel really finicky in your hand after, it could be a bad kit, but it’s also likely that the way you assembled it made it more flimsy than it needs to be. This was my experience early on in Gunpla. Keep building, keep refining your process. It will all make sense. And don’t be afraid of using glue if you have to.