I ripped out the control board of the 2x bay toaster and then bought some sata extension cables (with power) for 2x HDDs. 3D printed a little drive bay type thing and then slapped the raspi on top with the usb controller. It works great!
Works for my usecase of basic NAS /SMB /SFTP and I can stream 1080p etc.
But would look to sata in the future also like you mention, couldn’t find a hat, but USB speeds are fine for me.