It sounds like you've narrowed down the issue to the charging port of your iPhone 6 Plus. Here are some steps you can take to address the problem:
1. Clean the Charging Port: As with any device, the charging port can accumulate dust, lint, and debris over time. Gently clean the charging port using a soft, small brush, toothpick, or compressed air. Be very careful while cleaning to avoid damaging the delicate pins inside the port.
2. Check for Physical Damage: Examine the charging port carefully for any visible signs of damage, such as bent pins or corrosion. If you notice any damage, it's likely contributing to the loose connection issue.
3. Use a Different Cable: While you mentioned you've tried different cables, it's still worth trying another high-quality cable to ensure that the issue isn't solely due to a faulty cable.
4. Restart Your iPhone: Sometimes, software glitches can cause charging issues. Restart your iPhone to see if that resolves the problem.
5. Check for Debris in the Cable End: Inspect the ends of your charging cables for any debris or lint that might prevent them from making a secure connection with the charging port. If you find any, carefully remove it.
6. Try Different Charging Adapters: The issue might also be with the charging adapter you're using. Try different adapters to see if the problem persists.
7. Use a Dock or Stand: Using a charging dock or stand can help relieve stress on the charging port and reduce the chance of disconnections.
8. Contact Apple Support: If none of the above steps work, and you're confident that the charging port is the problem, it's a good idea to reach out to Apple Support. They can provide guidance on whether your device is eligible for repair or replacement. If your device is still under warranty or you have AppleCare, they might cover the repair.
9. Consider Professional Repair: If your device is out of warranty or Apple's support options are not feasible for you, you could consider seeking help from a reputable third-party repair service. They can assess the charging port and offer solutions.
Remember that attempting any repairs yourself carries a risk of causing further damage, especially with delicate components like charging ports. If you're not comfortable with DIY repairs, it's better to seek professional help to avoid worsening the issue.