You could check see if your m&p pistol release works in the fpc . Since the mags are the same it probably does . If it works the after market makes it easy to pick an extended model . Start with Springer Precision
FPC and M&P mag catches are not interchangeable. No one makes an extended FPC mag catch yet that I'm aware of.
Possibly see if customer service will sell you a spare mag catch and then you can make a project of extending the catch button with your home gunsmithing skills.
If "manipulating at speed" is the issue, try swapping the release left to right so you can operate it with your trigger finger. I've done that with mine that I use in IDPA matches every weekend. Quick enough for me.