[Xiaomi Redmi Note 5 Pro Questions & Answers] RandomNewbie:
Hey there! The general bootloader unlocking wait time is 30 or even 60 days since the 1. September. It can be shorter, or there is no wait time at all if you have used a Mi account to unlock other devices before. But it depends on their mysteriously mysterious system. From what I read, it can make a difference if a phone number is associated with the account. But I wouldn't count on it for new accounts. Better expect the full and brutal 30 days unlock period.

As you mentioned privacy, it needs to be said that MIUI - the stock ROM of nearly all Xiaomi devices - is quite talkative and sends back data to their servers. They hide it in their terms of services, except that you are prompted to accept these terms of services once you set up your device. If you don't mind it, it should be okay and you can use your device normally until you can unlock the bootloader. After all, Google is also there in form of their Play Services and watch your activity as well. Buuuut, if you truly want to preserve your privacy, it's best not to use the device normally until you get to unlock your bootloader. Personally that is what I did, but rather because I really need and like to have root access on phones I own. In my humble opinion, the increased bootloader unlock time is there to force users to use MIUI. Previously normal times were 3, 7 and 14 days. In conjunction with the ads they want to force onto their users, and the data they collect, this just makes sense if you ask me. Despite this, and to mention positive points again, their phones are still really great value for the money. The Redmi Note 5 has excellent battery life, good mid-range phone performance, takes nice pictures as well and is basically just a pleasant device. Though, if you plan to use LineageOS, you will need to install one of the Mi A2 camera or Google Camera ports if you want to use LineageOS without having to sacrifice camera quality. Actually, with the Google Camera port the pictures of this device get even prettier than they normally look like with the MIUI camera! Might be a matter of taste after all, but I tested it myself and can just confirm what others said about the awesome picture quality.

In case if you will need it for the future, here is a little link collection, all from XDA:

Bootloader unlocking process (slightly outdated since no application is necessary anymore, but still accurate enough): https://xdaforums.com/redmi-note-5-pro/how-to/how-to-unlock-bootloader-redmi-note-5-t3757685

Recovery to replace the stock one: https://xdaforums.com/redmi-note-5-pro/development/recovery-red-wolf-recovery-project-t3766997

LineageOS 15.1: https://xdaforums.com/redmi-note-5-pro/development/18-jul-lineageos-15-1-t3817814

Basically LineageOS, but even better: https://xdaforums.com/redmi-note-5-pro/development/ota-resurrection-remix-os-6-0-0-t3777375

Mi A2 camera port: https://xdaforums.com/redmi-note-5-pro/themes/miui-stock-camera-portrait-mode-dual-t3816069

Google Camera: https://xdaforums.com/redmi-note-5-pro/themes/app-arnova8g2s-google-camera-port-t3784423

Oh, and another side note. Should you decide to get the device, disable system updates in MIUI. Because of this: https://xdaforums.com/redmi-note-5-pro/how-to/faq-questions-answered-t3816185

Might look kinda scary to show you all of this, but I just want to let you know what you should know beforehand. Hope this helps you somehow! c: