You can perform a leakdown test and compression test in order to help I identify what you have going on there. White smoke to me sounds like a coolant leak, not an oil leak. Oil burns with a grayish blue color, not white. 

I plan to use AT-205 and monitor consumption levels. 

If you're describing what I think you're trying to describe, AT-205 won't do anything. AT-205 only works on rubber seals that have hardened and shrunk. It doesn't work on metal components. Scotty has used AT-205 on hardened rear main seals. AT-205 won't work if the rubber has been physically damaged and might make it worse. Rubber gaskets that have cracked are also no-good. The only option is replacement.

Posted by: @richard-couture

↑

After speaking to a mechanic, he recommended trying an oil stop leak before eventually needing to replace the engine.

Those products are basically all snake oil. If the engine is worn out,  it's worn out. There is no miracle "mechanic in a bottle" stuff. You might try replacing your PCV valve if you haven't already. 

Did you crack your head gasket? Try this: https://youtu.be/v0U8Iyf0kk4?si=VlaJgPgukkw5U__J  

It's likely Coolant or Engine oil burning inside the Chamber.

Lets assume its coolant, Coolant Quantity will deplete faster and you might want to check your coolant level often after driving your car for a good distance with the AC turned on.
Coolant burns are most likely associated with bubbling of the coolant when you open your Radiator cap in colder engine you can see coolant boiling due the the loss of compression gasses from the head gasket. That said, you may also have a blown up head gasket and further see oil leaks in due time.

Coolant burns are hard to find in exhaust fumes, if the leak is slow, all you have to do is check coolant reservoir when cold.

Secondly as I'm 90 percent assuming, lets say Its engine oil burning. Since you have replaced necessary valves. We can rule them out.

On startup of a cold engine, what happens for a few seconds is. The piston and its rings are not fully expanded in colder temperatures and does to form a correct seal lock in colder Temperatures. And oil leaks from the piston rings and combust with the air fuel mixture, thus resulting in white smoke.

As the engine chamber warms up gradually after few seconds, the piston, rings, sleeves, with heat, expand to their correct sizes and forms a tight seal, thereby after few seconds it does not let oil pass through them, there by not burning oil and white smoke has stopped. Engines are meant to be run hot, as their operating temperature, not cold. That's why its advised not to rev your engines right after startup as that's not the best temperature engine is to be run.

It is most likely your piston rings and sleeves have given up in one or more cylinders. And it may need a rebuild. You can do a compression test professionally to determine the compression leak.

You can drive your car until it passes emissions tests and does not emit much white smoke in traffic, you have to keep adding oil for every 500 miles.

Over time, Your spark plugs also keep failing as unburnt oil deposits, clog the spark plugs. Causing misfires and tripping codes.

White smoke is just visible on startup, but even later as you drive, engine still burns minute amounts of oil but you just cannot see them. When cold, put your finger in the tail pipe, it has to be dry like powder, if its greasy, your car is burning oil all the time.

Heck if you are a cheap guy like me, you can just drive adding engine oil additives, you can add engine oil of thicker viscosity, you have to keep changing spark plugs. If the mechanic verdicts that you need a engine Overhaul, its upto you. When you anyways need a new engine why not experiment by using oil additives or Thicker engine oil. Again Not recommended. It's for curiosity.

I remember adding myself a Truck engine oil to my Motorcycle which had same problem at startup. It still burned oil.

ATS is for rubber seals, Fuel additives are for Injectors. If you want to experiment Additives, they have to be directly added to engine oil.

Im not a Mechanic, it's my diagnosis as a enthusiast. I wonder why your Camry has given out such soon with less mileage. Better consult a Honest Mechanic like Scotty.