you are 100% correct the block is aluminum but many other wear parts, camshaft, crankshaft, piston rings, oil pump/chains and whatever else may be there usually are ferrous, I'm going to be as OCD as possible and throw magnets wherever I can.
You guys have it all wrong, they are not "watered down", all 235 width falken at3ws come like that even off the shelf. The 245 width has the meaty chunky sidewalls.
https://www.tirerack.com/tires/tires.jsp?tireMake=Falken&tireModel=WildPeak+A%2FT3W
Read the first review. Thats how the 235 gets...
Tried Amsoil products in the past but the marketing and explanation vids for Liquimoly products hooked me. They are also recommended by Blackstone labs.
Honestly oil filters can get particles down into the microns, 20 or so I believe. I'm super OCD and will be keeping this truck for 10+ years so before pickup I'll be getting some magnets to pop on the pan if its not composite, a magnetic drain plug after the first oil change, and filter magnets...