PLA
~100-150 years later
Variations of Gen 1 and Gen 3 story
3 years later
Variations of Gen 2 and Gen 4 story
3 years later
Variations of BW story
2 years later
Variations of BW2/XY story
2 years later
Variations of SM story
2 years later
Variations of SWSH story
2 years later
Variations of SV/PLZA story

Variations = general events of the gen's story but accounting for multiverse differentiations such as remakes, different versions etc

We know Gen 7 takes place 10 years after Gen 1 because Red and Blue are 20 years old in SM and Mina was in LGPE