Good evening Jason and welcome back!
Thank you for reaching out to us.
I would love to help you with this topic.
On most WordPress theme, the easiest to accomplish that is by going to Appearance > Customize > The Events Calendar > Global Elements > Button color.
You can also try adding the following CSS rule to your style.css file or in your Custom CSS metabox:
.tribe-events-button, #tribe-events .tribe-events-button {
background-color: #dd3333 !important;
}
Let me know if that helps.
Have a great day!
Geoff B.