For edge failure is there a way to feal with plinths? If the anchor extends below the plinth into a slab

Thank you for your question. I’m assuming your specific criteria is a baseplate being attached on the top of an existing plinth. If correct, then it might be worth checking to see if it is possible to treat the connection as being a grouted baseplate scenario under the new EN1992 Part 4 code as it does have improved shear resistance.