Can someone apply for a 90-day Non-O visa without a Thai bank account upon entering Thailand on a visa waiver?

No. You have to leave the country have it in your home bank account and get the 90 day. Come to Thailand open a bank account transfer the money marked as an international transfer then apply for the year extension.

The best option is to apply for a 3 month retirement e-visa from outside Thailand and use funds in a bank outside of Thailand. Then arrive and first job open a bank account and then deposit 800,000 wait 2 months and apply for 12 month extension

No, if you enter Thailand on a visa-exempt for 60 days, you cannot apply for an in-country initial non-O visa based on being over 50/ retirement without a bank account in Thailand unless your embassy in Thailand issues an affidavit of income. You need 800K baht in a Thai bank account OR an embassy affidavit for an initial visa application at the local immigration office.

If you want to open a bank account for an extension, you need to enter on Non-O retirement issued from the Thai embassy/consulate outside Thailand.