Yes, you can purchase Vivo V11 Pro via without credit card option. Check out this video - this will help you to understand the whole process.
Yes, You can record 4K videos with Vivo V11 Pro.
Yes, Vivo V11 Pro does have the OTG support.
Yes, Vivo V11 Pro does have the App clone support. You can run multiple social media and WhatsApp accounts.
The Vivo V11 Pro is a solid all-rounder at Rs. 25,990 and offers better value than the Oppo F9 Pro (Review), but for a bit more money. Think of it as a Vivo X21 with a bigger battery and better front camera, but at a much more reasonable price, which is a good recipe.