The other day on YT bike race video, I've seen barriers that are flat all the way down to ground and with only flat feet jutting into the road. They probably have longer feet on the spectator side to keep them stable. I shudder when I see those barrier feet that at a foot height start arching out and down into the roadway...
Some interlocking (to prevent a barrier section flying like we've seen in this accident), even if just dry zip strips or plastic ties would be probably sufficient if the barriers were covered by a continuous strip of some tough material - like that one used on political voting banners on people's front lawns, the one with air channels between the two faces... that is quite tough material as everybody knows who tried to dispose of it after the elections
All barriers around a course should not have feet that stick out and interlocking and covering them could be reserved just for the finish line, last couple hundred meters or even one hundred...