I completely agree with you, ever since my dentist strongly encouraged me to floss, I feel disgusting when I don't do it and can only shake my head at my previous ignorance, thinking that mouthwash is good enough (that's rubbish!).
The only thing I don't agree with is the use of the plastic helpers. I don't think I need to contribute to plastic pollution for a tiny bit of comfort. I got used to the regular floss within two or three days.
On top of you advice: IMO if the tap water is safe for drinking, use that and don't buy bottled water at all. No need to add to the plastic problem. Also: it's usually cheaper.
Huh. I would love this.
But can I without Signal, WhatsApp & Co?