OP says tires are 2 and 4 years old. OP said nothing at all about uneven wear.
And 4 years is still pretty young for tires. I grew up hearing “10 years” as a rule of thumb for when to toss tires due to age; more recently, 7 years seems in vogue.
Neither limit is terribly close to being exceeded by the tires on the car. I swear, you could cover 40 acres with the number of perfectly servicible tires some of you would condemn to the dump!