AI method is a huge pain you have to calculate yourself the quarterly AGI, withholding, qualified divs, cap gain etc (uneven quarters thru 3/31, 5/31, 8/31, 12/31) it's like doing 3 extra tax returns, you may have to do it for state also. It's helpful if you have an unplanned Q4 event like Roth conversion and need to pay one-off ES late in the year; if you have a big income event in Q1 you can always estimate and plan quarterly ES anyway, there is no need to pay all the tax in Q1 for it.
If you have a big jump in income such that 100/110% prior year tax is the lower safe harbor then take advantage of that rule. You will have a known, fixed quarterly ES payment (assuming you meet any planned withholding for the year) and it won't matter the timing of your unpredictable income or how much it is. There is no "appearance" of underpayment, it you meet the requirements of Form 2210 you will not have a penalty. Hence the term "safe harbor". You still need to have a good estimate for 2026 and set aside what you owe in April 2027.
As for the concern IRS may adjust your 2025 return to the extent you owe more tax resulting in a significant change of ES and penalty, that sounds like a very low risk (depending your situation). If it happens you would just need to catch up ES payments to the new level and may have some penalty for earlier quarters (e.g. if you find out beginning of June you owe $4000 more ES that's $1000 per quarter, you know it time to adjust for Q2 onwards, and you'd pay an extra $1000 right away to stop the penalty on Q1 - for about 2 months the penalty will only be $1000 * 0.07 * 2/12 =$12). If really concerned about this you could also overpay Q1 to create some contingency, if nothing changes any overpayment from earlier quarters carries forward to later quarters and you can pay less later, it's just lost interest for you. Unless you have something uncertain or questionable about your 2025 return I wouldn't worry about it.
Personally I did AI method for 2024 due to Q4 Roth conversion, it was a huge pain and probably took as much time as my original return, then I had to do it for state also. To avoid this for 2025 I paid ES based on prior year and did the Roth conversion right away in Q1 as timing was not an issue - no AI method, no penalty.
If you are using Desktop TT you can play around with 2025 s/w to mock up 2026 return (albeit with 2025 tax tables or deductions but will be in the ballpark) and plug in different income and ES payments and view Form 2210 in Forms mode to see there is no penalty regardless of how much income you make as long as you meet safe harbor based on prior year tax (use Other Tax Situations / Underpayment Penalties to set the prior year tax and AGI).
Not a CPA but that's my understanding based on what you described, hope this helps.
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