Correct transition for pvc conduit to liquid tight flexible conduit on a concrete slab
Your plan will work but depending on the distances in each direction, pulling the large wires that a hot tub requires could be tough. Think about using a PVC LB similar to the one pictured below. It's neat and clean and you can pull wires much easier with the LB access. You would have to stub a small  piece of PVC to the LB and use a female adapter to accept the liquid tight straight connector(Thanks to @ThreePhaseEel).