Hi there - welcome to the cheatgame.info community!
It’s great that you’re working to improve your credit! We’re looking forward to being a resource for you along the way.
Yes, you should expect a small dip in your score from the hard inquiry initiated by applying for another card. One thing to keep in mind when opening new accounts is that the “number of accounts” credit factor generally comprises a very small percentage of your credit score. Which means it’s possible to have an excellent credit score with only 1 or 2 accounts. While the models do favor more accounts, and specifically different types of accounts - as they want to see that you can use different types of credit (e.g. revolving vs. installment) responsibly - it’s ultimately a tiny factor in your credit score and shouldn’t prevent you from building excellent credit.
You can read more about what makes up your credit score here:
Unfortunately, I can’t say for sure if you’ll be able to add 50 points to your score between now and Christmas. However, I can say that staying well below credit limits and building a record of on-time payments can have a big impact in a short time.
Check out this resource for some great tips:
Is there a specific reason you’re looking to raise your score to 700 by Christmas?