I've been experimenting with different blackberries, trying and mostly failing to grow raspberries ( I'm right between where tropical ones and regular ones will grow ) and bought a lot of plants from a lot of different berry growers.
One nursery stands out as being way higher quality, so high none of the others I ever got even came close.
https://www.noursefarms.com
I spent a lot of money on sub standard berry nursery stock before I found Nourse.
Some of the other suppliers plants are still struggling along, the rest long dead.
Blackberries love it here naturally so if I get stock that struggles I know there's a problem with quality.
Nourse has all the new thornless primocane and floricane (summer bearing and everbearing, Summer-bearing: fruiting in mid-summer. Everbearing: fruiting in late-summer into fall.) fruiting blackberries like prime ark freedom.
Those new ones are all patented plants and I know many object to that.
They also have the older good quality non-patented thornless ones like Chester.
They have an excellent berry growing "how to" on their website:
https://www.noursefarms.com/growing-corner/planting-guide/