Hi OP!
There are lots of reasons you might have trouble with your PF.
Strength or conditioning of the muscles is one. As a self test, see if you can clench your vaginal muscles tight, then relax to "50% on". You should be able to hold that for 60 seconds, without the muscles tiring. If that's tricky, you probably need to do more strength work. That can include using weights. Aquaflex is one tool, you used to be able to buy it off Amazon for about £20.
If you want online tutorials, Denise Conway on YouTube is good.
However, it is not just strength.
You also need to be sure your muscles are not too tight or even in spasm. This can happen with weak muscles. You should also stretch gently every day. A wide-legged child's pose or happy baby position is great for this.
Finally, it can also be related to other muscle groups. The PF interacts with other nearby muscles such as glutes, which are much bigger than the PF. They can pull on it. So if they are weak or not "firing" right, it can affect how your PF works. Sometimes, you may need to encourage those muscles to fire, such as by doing one legged squats to engage them. Or stretch them. A physio will help with this.
I would suggest you get some weights and use them regularly plus start stretching too. At the same time, if you have the means, look for a private women's health physio in your area, and don't be afraid to shop around till you get the right one!
Good luck