Impact of a 'T' grade or multiple GMAT scores

Hi all! I posted on the test experience forum and was suggested to ask my question here instead. I'd be really grateful if any of you could help answer some of my questions!

I took my GMAT a month back and accepted my score at the test center as I was unsure if I wanted to cancel it or not. The next day I was sure I would retake and wanted to cancel the score but there was no option to cancel on the website even after 48 hours of the exam. I emailed them and also called customer support and they said they raised a ticket and gave me a case number. After a month of back and forth with them (which was extremely stressful and exhausting), they are saying that despite the issue I faced, they can't really cancel my scores since it's past the 72-hour window but they can revoke my score if I so wish. My score report would then show a 'T' for the next 5 years. I'm not sure how helpful that would be because I've never heard of anyone having a 'T' for a test center exam. Despite the fact that they say that the 'T' indicates that the issue was out of the candidate's control, I'm not sure how schools would perceive that. So, I wanted to get your thoughts. I have 3 major thoughts right now:
I'm definitely going to retake and the plan to get at least 730 (goal is 740/750). But if in case I'm unable to break past 710/720. Would a 690-710 look better or a 'T'-710? What's the minimum I should accept such that the 690 becomes a non-issue?
I'm not sure how much I should pay heed to this issue now since it has already taken up too much of my time and energy. I just had to get an answer because it was a mess up on their end but now their answer doesn't really seem to change the situation much and I feel like I should focus on other things. Is there anything else I can do now?
If I keep the 690 and then score higher, would I need to address the previous lower score in my essay somewhere?
Thanks in advance for your thoughts and suggestions!