Safety precautions when making a commercial electronic product
This device is an intentional radiator  (it transmits RF) so it will be relatively expensive to get it certified for all jurisdictions. Safety is on top of that.
Your product may be otherwise well designed with what you think are good protections, but if a single-point failure can cause a fire or electrical shock then it may need to be modified. If every part that comes near the mains is plastered with listings and your design is decent it will be a lot easier/faster/cheaper. They don't care so much if your product is reliable or useful, the focus is solely on whether it can cause harm in one of a number of ways. For example, the plastic housing may need to be made of an appropriate resin with fire retardant additives to be approved, but certain fire retardant additives are banned in some jurisdictions.
So maybe decide where you want to try selling it and research which standards apply (often there are gray areas) and get ahold of copies of the relevant standards.