Do these release buttons ever freeze up? I am having trouble getting mine to work.

Hi

To remove the band: hold down the band release button, then slide the band across to remove it, whilst keeping the button pressed down.

If your metallic band is the Link Bracelet (rather than the Milanese Loop), first separate the Link Bracelet into two pieces before removing it from your Apple Watch.

More information:

Link Bracelet: Remove the Link Bracelet on your Apple Watch - Apple Support

Other bands: Change your Apple Watch band - Apple Support

If you are having problems releasing the band, maybe you should clean your watch around the button.

I would follow the steps from cleaning the digital crown if that doesn't help. Note on the normal cleaning they say to use a dry or damp cloth but on the Digital Crown cleaning, they say you can use warm running water.

Normal cleaning - Cleaning and wearing Apple Watch - Apple Support

Digital Crown cleaning - Get help with the Digital Crown on your Apple Watch - Apple Support