[Dúvida] Como eu salvo entidades relacionadas?

Estou tentando salvar 3 objetos relacionados no banco de dados, mas não faço ideia do porquê não funciona.

Log:

2023-01-27T01:15:08.960-03:00  INFO 8532 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2023-01-27T01:15:08.960-03:00  INFO 8532 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2023-01-27T01:15:08.961-03:00  INFO 8532 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 1 ms
newTso executado em 0Ms
Iniciando novoTso
toTso chamado
toTso concluido
2023-01-27T01:15:33.190-03:00  WARN 8532 --- [nio-8080-exec-5] o.h.a.i.UnresolvedEntityInsertActions    : HHH000437: Attempting to save one or more entities that have a non-nullable association with an unsaved transient entity. The unsaved transient entity must be saved in an operation prior to saving these dependent entities.
    Unsaved transient entity: ([br.com.fanthom.boot.model.Cliente#<null>])
    Dependent entities: ([[br.com.fanthom.boot.model.Tso#<null>]])
    Non-nullable association(s): ([br.com.fanthom.boot.model.Tso.cliente])
2023-01-27T01:15:33.193-03:00 ERROR 8532 --- [nio-8080-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed: org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.TransientPropertyValueException: Not-null property references a transient value - transient instance must be saved before current operation : br.com.fanthom.boot.model.Tso.cliente -> br.com.fanthom.boot.model.Cliente] with root cause

--

package br.com.fanthom.boot.model;

import java.math.BigDecimal;
import java.time.LocalDate;
import java.util.List;

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.JoinColumn;
import jakarta.persistence.ManyToMany;
import jakarta.persistence.ManyToOne;
import jakarta.persistence.Table;

@Entity
@Table(name = "tsos")
public class Tso {

    @jakarta.persistence.Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long Id;

    private BigDecimal ValorTotal;

    @ManyToOne
    @JoinColumn(name = "Cliente_id", nullable = false)
    private Cliente cliente;

    private LocalDate dataDaCria;

    private LocalDate dataDaEntrega;

    @ManyToMany
    private List<Produto> produtos;

    public Tso() {
    }

    //getters e setters omitidos...

--

package br.com.fanthom.boot.model;

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.JoinColumn;
import jakarta.persistence.OneToOne;
import jakarta.persistence.Table;

@Entity
@Table(name = "Clientes")
public class Cliente {

    @jakarta.persistence.Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long Id;

    private String nome;
    private String tel;
    private String cpf;
    private String email;

    @OneToOne
    @JoinColumn(name = "Endereco_id", nullable = false)
    Endereco endereco;

    public Cliente() {

    }
    //mais get e set...

--

package br.com.fanthom.boot.model;

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.OneToOne;
import jakarta.persistence.Table;

@Entity
@Table(name = "Enderecos")
public class Endereco {

    @jakarta.persistence.Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long Id;

    private String cep;
    private String rua;
    private String numero;
    private String bairro;
    private String cidade;
    private String comp;

    @OneToOne
    private Cliente cliente;

    public Endereco() {

    }

--

package br.com.fanthom.boot.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

import br.com.fanthom.boot.dto.RequestNovoTso;
import br.com.fanthom.boot.model.Tso;
import br.com.fanthom.boot.repository.TsoRepository;

@Controller
@RequestMapping("tso")
public class TsoController {

    @Autowired
    private TsoRepository tsoRepository;

    @RequestMapping(method = RequestMethod.POST, value = "novo")
    public String novo(RequestNovoTso request) {

        System.out.println("Iniciando novoTso");

        Tso tso = request.toTso();
        tsoRepository.save(tso);

            System.out.println(" novoTso executado :)");

        return "tso/formulario";
    }