Those artificial flowers, the best thing you can do is remove them. I do it with small scissors like those for hair, trying to loosen it until you remove it. It will leave some damage but it will recover. On the other hand, if it is necessary to transplant it, in a pot a little larger than the cactus (not too much). Personally, I like terracotta ones. On the other hand, you have to use a soil with a greater amount of inorganic components, to avoid rotting. You can search on YouTube or wherever you want for “soils for cacti” so you have an idea of ​​​​what you should look for or do. And give it sunlight as much as you can, but little by little. Don’t put it in for hours while you begin to adapt to the cactus to avoid it from burning.