If the iPhone 14 Plus is now available and you encounter an issue with the back glass, here are some general guidelines to consider for back glass replacement:

1. Apple Authorized Service Provider (AASP): Taking your iPhone 14 Plus to an Apple Authorized Service Provider is typically the recommended option. They have trained technicians who are familiar with the latest models and can perform repairs using genuine Apple parts. If your device is still under warranty, this option is especially advisable to maintain the warranty coverage.

2. Apple Store: You can visit an official Apple Store for back glass replacement. They offer similar services to the AASP and use genuine Apple parts.

3. Third-Party Repair Shops: Third-party repair shops may also offer back glass replacement services for the iPhone 14 Plus. If you opt for a third-party repair, make sure to choose a reputable and reliable repair shop. Keep in mind that using non-genuine parts may void the warranty with Apple.

4. DIY Repair: DIY back glass replacement can be challenging, especially for newer iPhone models. If you have experience with electronics and phone repairs, you can attempt it, but be aware that it might void your warranty if you accidentally cause further damage to the device. Ensure you have the necessary tools and replacement parts specific to the iPhone 14 Plus.

Always exercise caution when attempting any repairs, especially with new and expensive devices. If your iPhone 14 Plus is still under warranty or covered by AppleCare, I recommend checking with Apple or an authorized service provider for the best course of action. They can provide guidance on the repair process and potential costs involved.