If you get accepted to your ED school and have applied for financial aid, you will also get your aid package with acceptance. If the aid is not enough for you to attend, you let the Admissions office know immediately. You may be directed to financial aid office to see if any adjustments can be made. If the package is way off from the Net Price Calculator on the college website which should have already run to make sure the school was financially feasible for you, or if you have financial issues not addressed by the NPC, you have excellent reason to withdraw from the ED commitment. That failsafe clause is in the contract that you signed.
The drawback with ED and financial aid is that you cannot compare financial aid packages. You have to decide you can do it with the ED package offered or decline it and take the chance you can get better . Imo , it usually is a very good offer. Colleges want to get as close to 100% yield as they can with ED and the coffers are full early in the admissions season. Come RD they are often running lean , they have so many packages they have to put together, and they are harried for time.
I suggest running the NPCs on several like schools and see what such colleges are expecting your family to pay. If it’s not affordable, given what your parents are willing and able to pay, ED is not for you, because it’s rare you’ll get any merit notifications early, and merit is often used to coax students to commit— they already have your commitment with ED