You can interact with buttons through the use of projectiles whilst in spawn protection

• Start a server and join it
• Give operator permissions to yourself
• Set the world spawn to your current location
• Place a button anywhere within the spawn protected area
• Place a block that can interact with redstone next to it
• Acquire a bow/crossbow or a trident
• Remove your operator permissions
• Give the operator permissions to a different player
• Throw the projectile at the button
  -Notice how it's activated and able to power adjacent redstone components