Is it possible to use external SSD with Pi4 to boot to HA?

Trying to avoid using SD Cards.

Can the Home Assistant Pi image be installed and run from an external SSD attached to a Pi4?

Yes, and there are sooo many guides available. Just search for it, and find one that suits you best.

Only tip of advise: make sure you get a sata to usb converter that is supported. Google that list too to have the latest and most up to date list to ensure full compatibility.

This is what I followed, worked fine for me: https://youtu.be/Ks-GxF6sd5M

Since HASSOS is at 5.11 now, is downloading the beta still required? Do you know if 5.11 has the capability of running an external SSD?