I did manage to collect some black highbush blueberry and wild blueberry for seed saving.
I saved the black blueberry last year and cold-stratified them outside by just burying the berries in pots and only one came up. This year I’m saving the seeds in the fridge in moist vermiculite to see if it works better.
Pic: top left is domesticated blueberry from my garden, top right is black highbush blueberry and bottom is wild blueberry.