You just want to text family, send photos, and keep your old phone as a backup device.

For Android 4.4.4, you should target specific legacy versions designed for "Android 4.4+" (API 19):

To install Facebook Messenger on an Android 4.4.4 (KitKat) device, you must use an older version of the app, as modern releases from Google Play Store typically require Android 5.0, 7.0, or even 9.0 and higher. Compatible APK Versions

Yes, but quality will be poor. Video codecs improved after 2021. Expect lag and potential crashes on 1GB RAM devices.

Using your Android 4.4.4 device’s browser: