Hey JooSung!
No need to apologize — you're asking exactly the right questions, and I can tell you're serious about improving. Plus, I'm here to help. :)
It's completely normal to feel overwhelmed, especially given your time constraints and the pressure you feel. Here are my thoughts. I hope they help. :)
1. Your score of 1410 on the SAT is in the 94th percentile, so it's already a high score. Great job!...but I know you're aiming for higher. A 1410 on the SAT converts to a 31 composite ACT score.
Composite score calculation: ou're given a score from 1-36 for each of the three core sections: reading, english, math; by the way, you're right the science section is optional (Question 6). The essay is also optional (Question 3), but check the requirements for the schools you're targeting or applying to because some schools require an essay score (most schools don't). Then the scores are averaged to determine your composite score, and if your composite score ends in .5 or above (e.g., 32.5, 33.67, etc..), it rounds up (e.g., 32.5 --> 33; 33.67 --> 34).
It is possible to achieve a high score on the ACT, but it depends on many factors. However, it is worth mentioning that it takes students time to adjust to the ACT because it does test some different cognitive and reasoning skills (although there is some overlap in skills). Plus, time management is something that students need to make adjustments for as well (it feels faster than the SAT, although the new ACT will provide students with more time per question).
The best advice I can give you, which will help answer a lot of the questions you have, is to take a full-length diagnostic ACT exam. That way you can (1) get a feel for the time (compared to the SAT), (2) the types of questions, (3) the level of difficulty compared to the SAT, and (4) an estimated score, which will give you a starting point and a good sense of whether you can hit your target score by test day.
After you take the ACT practice test and receive a score, decide whether you will pursue the ACT or the SAT. I would not recommend doing both because you'll be spreading yourself too thin. Instead, choose a test and COMMIT ALL YOUR TIME, ENERGY, AND FOCUS to that ONE test. You'll be surprised what commitment and purpose will do. :)
4. My ACT English Foundations course does not contain the Reading section or the essay; it only contains the English section (think of the English section like the 'grammar' section...sentence structure, punctuation, pronouns, transitions, etc..). It is also worth mentioning that my ACT English foundations course is for the OLD ACT. Although the concepts and question types are the same, the number of questions and the format of the English section is different. I'll be in Korea this summer to create an updated course for the new ACT English section. :)
7. This site does a good, clear job explaiining the structure and format of the New ACT. If the link doesn't work, you can copy and paste the URL: https://www.kaptest.com/study/act/test-changes-2025/?srsltid=AfmBOop_ClbfKVkJf05BCBkVVrwiFEyQmpQ_SZI7f3VceyN2RkU1tnY
Finally, the ACT website has an online practice test that you can take (just one). If the link doesn't work, you can copy and paste the URL: https://www.act.org/content/act/en/products-and-services/the-act/test-preparation.html
I hope this helps!
Whatever you decide, best of luck!
You Got This!
Jin