Secure Erasing Internal SSDs Using File Vault

I am the "middleman" in an effort to collect old, unused Apple devices from seniors living in an aging-in-place community. My intention is to collect their devices, wipe them clean, then donate them to a local charity resettling Afghan refugees in the immediate area. Erasing HDDs I understand. Erasing SSDs is where I need guidance. I suspect all the donated computers will be 2016 or before and most will be laptops. I read that if I turn on FileVault, encrypt the SSD, boot into Recovery mode and erase the SSD, that will be the equivalent of securely erasing an HHD with one or two passes writing ones and zeros. Is this correct - I feel a very strong obligation to those donating old computers to get this right.