Is JPA bad choice to deal with EAV Data models?

I have been trying to use JPA/Hibernate to CRUD operate an EAV data model and have been facing lot of performance hit. I am looking for ideas to efficiently manage EAV data models.

**(A)**So here is an example of what I am trying to deal with, I have three tables :
UserTable
AttributesTable
UserAttributeValueTable

**(B)**And apart from these three, I have other relations like :
ItemTable
UserItemsRelationTable

So basically, AttributesTable is a table that contains all the attributes, may it be User's or Item's. And UserAttributeValueTable is the table that joins UserId, AttributeId, and a value.

Now, let's say I want to pull all the users and their attributes.

Here is how I mapped them :

 @Entity
    UserTable{     
          @Id
            @GeneratedValue(strategy=GenerationType.AUTO)
            @Column(name="USER_ID")
            private long userId;

        @OneToMany(targetEntity=UserAttributeValueTable.class, mappedBy="userTable", fetch=FetchType.LAZY)
        private List<UserAttributeValueTable> userAttributeValues;

    //Other Columns

        }

        @Entity
        UserAttributeValueTable{

            @Id
            @GeneratedValue(strategy=GenerationType.AUTO)
            @Column(name="USER_ATTRIBUTE_VALUE_ID")
            private long userAttributeValueId;


            @Column(name="\"VALUE\"")
            private String value;

            //bi-directional many-to-one association to AttributesTable 
            @ManyToOne(targetEntity=AttributesTable .class ,fetch=FetchType.LAZY)
            @JoinColumn(name="ATTRIBUTE_ID")
            private AttributesTable attributes;

            //bi-directional many-to-one association to UserTable 
            @ManyToOne(targetEntity=UserTable.class,fetch=FetchType.LAZY)
            @JoinColumn(name="USER_ID")
            @JsonIgnore
            private UserTable user;

        //Other columns

        }


    @Entity
    AttributeTable{

        @Id
        @GeneratedValue(strategy=GenerationType.AUTO)
        @Column(name="ATTRIBUTE_ID")
        private long attrId;

        @Column(name="ATTRIBUTE_NAME")
        private String attrName;

        //Other columns
    }

Problems : 1. I ran into an infinite loop when I did a findAll , and that was obvious,so I used @JsonIgnore so that it would ignore the UsersTable. However, to retrieve 300 User's(User Attribute Values), it is taking a lot of time and I am not looking for every column either. All I want is to flatten it this way:

User :[{ id:"1", name:"John", otherAttributes={attr1:"value1",attr2:"value2"},{ id:"2", name:"Joey", otherAttributes={attr1:"value1",attr2:"value2"}]

2. Mapping complexity, when mapping with other kind of relations like (B)

I just felt after writing simple SQL queries would be more easier in these kind of dynamic models where the column is a not a field instead it is a property. Any suggestions ?

I am using Spring Data JPA.