I think differences are going to be marginal between PS4 and X1 or PS5 and XSeX. You'll have the low end versions on Switch and you'll have the high end versions on PC. Then the new consoles are the mid-tier. As for last gen, it was the same then. As WeirdFeline stated, I think PS4 at launch up until the mid gen upgrades of hardware was slightly better. Then once the X1X and Pro released, the Xbox had the edge. Not every title of course and the differences would be, again, marginal.
Maybe Digital Foundry would have exact differences on some games?