I have read this thread. I myself have the same dilemma. I think the misunderstanding is the houses used to be grounded to the water pipes. I now have new Pex plastic pipes, so now my house is NOT grounded. My question, “How do I fix this problem”? And yes it was built and wired with 2 prong outlets everywhere.
I get where your endgame is just to plug in 3-prong plugs; OK, the easy shortcut there is fit GFCI receptacles or breakers.
However, if you want real grounding that you will depend on for safety and equipment protection, then you need to start at the grounding rods.
The source of grounding (earthing) is the grounding rods going into the earth. These could be water pipes if metal, an UFER ground if built into the foundation, or grounding rods driven into the earth at the correct locations.
From these rods, a grounding electrode carries the ground to the main panel. At the main panel ONLY, there is a bond between ground and neutral. Allowing them to bond anywhere else can create a safety problem.
From the main panel, ground wires go to each subpanel and up each circuit. Ground wires can be retrofitted, and we have questions which discuss retrofitting grounds.
Again, it must start at the grounding rods and go via the main panel. Do not "island" grounds; don't have an area where the house where the grounds connect to each other but not to the main panel and earth. This only spreads the danger: if one device has a ground fault, it electrifies the chassis of all of them.
It sounds like you are struggling with some of the things we are talking about. We can't provide a full explanation of all things electrical which relate to this issue; that is not our format here. But you'll need that to be successful. Blundering ones way through electrical work is a fire or shock waiting to happen, and knowledge is such an easy thing to acquire.
You will need to install a residential grounding electrode (grounding rod). It is an 8-foot length of rod, driven into the ground outside the home and connected to the neutral side of the main panel with a copper cable. Its job is to channel electrical surges away from the home and into the ground. They vary in size depending on the service you have.
NEC 250.52(A) (5)(b) states, “Grounding electrodes of stainless steel and copper or zinc coated steel shall be at least 15.87 mm (5/8 in.) in diameter, unless listed and not less than 12.70 mm (1/2 in.) in diameter.”