Do you have scales which self-report because this has been on my wish list for a while now? It seems like it should exist: scales with a BLE read out that dumps out the value after a number has been stable, and flags it if I hit a button on the scale.
There's a whole range of products here which seem like they should exist but just don't (but I hardly want to do a hardware startup).
I do this with the Xiaomi Mi Scale 2. You can connect it to Home Assistant. Once it has a stable reading, it auto-submits, but there's no button for flagging, although you could potentially build this yourself. I never had to connect the scale to the internet; it just worked with Bluetooth