Right so this is exactly the kind of thing that keeps me up at night, not in a bad way just in a "my brain won't let it go" kind of way. I had something similar back in 2021, hovering over the park near my flat in Salford, no sound at all which is what got me. Anything with rotors you hear them, drones especially have that horrible whine to them. But this was dead silent.
What I'd really want to know from you is how long it stayed in one spot. Duration and the silence thing are the two biggest factors for me when trying to rule out the mundane stuff. Also did you manage to get any footage or even just audio? Even a recording of silence can be useful, sometimes you pick up infrasound on a decent mic that you can't actually hear in the moment.
Genuinely don't think you should try to explain it away too fast. Post what you remember here while its fresh, every detail matters more than people realise.