As a US citizen you’re entitled to a 60 days visa exemption upon arrival and in the discretion of the IO you meet in the immigration. You can’t get a re-entry permit on a visa exemption, so technically you’ll get two 60 days visa exemptions. If you prove a ticket out of Thailand within 14 days when returning from the Philippines you should be fine with this without applying for any visa.
I have three bank accounts in Thailand opened myself for several years, but you obviously don’t know the situation and catch 22 people are struggling with now regarding bank accounts and visas/long term stay in Thailand.
No, previously you sometimes needed to purchase an insurance at 5900 baht as well, but if you’re on a visa exemption or tourist visa, 10K baht for opening an account is not the worst option to day as things has become.
Health insurance is important, but important is also to be able to choose your own insurance, and not being stuck to a mandatory list of Thai health insurances approved by the immigration. Not only a coincidence that several people choose to cancel their stay based on a Non O-A after a while and re-enter and start from scratch with a regular Non O.