Honestly you can't trust a lot you see in ads. You can't even trust your manufacturer or the dealership selling the cars. Some brand new cars are sold with TSBs that haven't been fixed or addressed. I use https://www.carcomplaints.com/ when I'm shopping for a car to know which used cars to avoid.
There IS however a requirement to fix any recalls before a car can be sold, at least in the USA. But there are MANY more TSBs than recalls.
My Honda Odyssey has a TSB for the transmission basically eating itself. The fix is a full transmission fluid change (3x drain and fill) and a firmware flash. My van is beyond the mileage where the dealer would do this under an extended warranty specific to this TSB, but I've never actually experienced any of the symptoms mentioned in the TSB. Van is a 2016 with 115k miles on it.