Unable to access my iPhone 6 Plus after repair

Sorry, but are not allowed to discuss self-repairs on older versions of the iPhone.

You have installed non-genuine parts, so unfortunately you should expect problems with the touch screen not operating correctly.

All that we can do is recommend that you take the phone to an authorized Apple service shop to see if they would be willing to take a look at your phone.

You can find a list of authorized shops in your area using this link: Find Locations

Good luck.

Passcode

Your data is not lost if you have a backup either on iCloud or iTunes.

If you see an iPhone or iPad unavailable message or a "Security Lockout" screen

If you forgot your passcode, you can use your Apple ID and password to erase and reset your device without a computer.

Learn what to do if you see "[Device] unavailable" or "Security Lockout" on your iPhone or iPad.)

iPhone is disabled.

Following this process is the only way out if your iPhone is disabled. The steps given in this link will help you reset the passcode -> If you forgot the passcode for your iPhone, iPad, or iPod touch, or your ...

Regarding your data…

1. If you have an iCloud or iTunes latest backup, then there is nothing to worry about. If not read more...
2. You have synced your data to iCloud, then what you will get back is what you have synced to iCloud and uploaded to iCloud Drive; the information that is synced and stored in iCloud are, Contacts, Calendars, Bookmarks, Mail, Notes, Voice Memos, shared photos, iCloud Photos*, Health data, call history, and files you store in iCloud Drive. (*-If you have turned on iCloud Photos, your content is automatically stored in iCloud.)
3. You have imported your Photos and videos to Mac/PC then they are safely residing there on Mac/PC
4. You have uploaded some of it to Cloud Drives using the Files app (iCloud Drive, Google Drive, OneDrive, DropBox, Flickr, box, AmazonDrive, Adobe Creative Cloud, etc). The data remains there.
5. If you have not backed up or do not have the latest backup, nor imported nor you have synced or uploaded your data to cloud drives prior to the situation that you are in, then I am sorry, all your data is lost.

Password

Apple ID and Activation Lock

iCloud uses Apple ID credentials.

If you do not remember the Apple ID Password then follow the steps given in this Apple Article -> If you forgot your Apple ID password - Apple Support

If you do not remember the Apple ID then follow the steps given in this Apple Article -> If you forgot your Apple ID - Apple Support

If you are the owner or the owner has shared all information with you then to open Activation Lock:- If it is Activation locked, read here --> Turn off Activation Lock - Apple Support Activation Lock for iPhone, iPad, and iPod touch - Apple Support

Learn how to remove a device from a previous owner's account.

If you are not the owner and do not have the Apple ID and Password then there is no way that you can get into this iPhone unless the original owner shares the Apple ID and password with you. If you are lucky you can get into this iPhone if they (owner) accidentally remove the device from their Apple ID.

If you reset your passcode in the last 72 hours and have forgotten it, read this article about a special reset service available in iOS 17 and higher. --> Temporarily use your old passcode when you forget your new passcode on iPhone or iPad - Apple Support

If you see a waiting period you can try again after the timer ends. If you wish to proceed with resetting, or if it is disabled/security lockout/unavailable, refer to this support article for various methods that you can use to resolve this. --> If you see a iPhone, iPad, or Apple Vision Pro unavailable message or Security Lockout screen - Apple Support Which one you can use depends upon your equipment configuration. If you can use the iOS15.2+ method you may not need a computer.

How to reset your device if you are running iOS 15.2 or later:

Advance step: If you're using an eSIM on iOS 16 or earlier, contact your carrier before trying these steps and ask for a QR code to set up your eSIM again.

1. From your device's Lock Screen, try to enter your passcode five times until the "[Device] Unavailable" screen appears and your device asks you to try again later.

2. When you're able to, continue to enter your passcode until the "Security Lockout" screen appears and you get the Erase [Device] option in the bottom corner of the screen.
 3. Tap Erase [Device], then tap Erase [Device] again to confirm.

4. Enter your Apple ID password to sign out of your Apple Account on your device.

5. Tap Erase [Device] to permanently delete all of your data and settings.

6. When your device restarts, follow the onscreen instructions to set up your device again, restore your data and settings from a backup, and set a new passcode.

You can only reach the "Security Lockout" screen if you have an active cellular or Wi-Fi connection and previously enabled Find My ( Find My - Official Apple Support ) on your device. After you try to enter your password ten times, your device will either erase itself or show Security Lockout and the option to Erase [Device] without a timer, depending on how you previously set up your device. 

If you can't follow the above steps (e.g., you are using an older iOS version), you can use a computer to reset your device, as described in this article --> If you forgot your iPhone passcode or your iPhone is disabled - Apple Support .

Whichever method you use will result in erasing the iPhone. You have no alternative. You can, however, restore it from a backup as described in this support article --> Restore your iPhone, iPad, or iPod touch from a backup - Apple Support Some items will restore automatically once you make sure you are signed into iCloud (if you were using iCloud to sync these services).

Here are resources if you are prompted for your username and password and have forgotten them:

If you forgot your Apple Account primary email address or phone number - Apple Support Note that typically this is an email address you use.

If you forgot your Apple Account password - Apple Support

If you do not have a computer, use the link Find Locations to find an Apple service location, or ask a friend if you can use theirs. This could be either a Mac, or a PC with iTunes. If your computer doesn't recognize your iPhone, iPad, or iPod, read this support article --> If your computer doesn't recognize your iPhone or iPad - Apple Support