The 24-hour trial for the browser extension is less strict than the full desktop app. However, you will not get full system-wide protection.
Searching YouTube or Reddit will yield dozens of videos claiming to have a one-click "CyberGhost 8 trial resetter" or a registry hack. cyberghost 8 trial reset
The 3-day Android trial does require a payment method, but you can cancel immediately after starting the trial and still enjoy the full 3 days. Simply go to the Google Play Store → Subscriptions → Cancel. You won't be charged as long as you cancel before the trial ends. The 24-hour trial for the browser extension is