Minimum VR EventSystem components

VRInputModule.cs

using System.Collections.Generic;
using UnityEngine.EventSystems;

namespace FrameSynthesis.XR.UnityUI
{
    public class VRInputModule : BaseInputModule
    {
        readonly List<RaycastResult> raycastResults = new List<RaycastResult>();
            
        public override void Process()
        {
            var pointerEventData = new PointerEventData(EventSystem.current);
            eventSystem.RaycastAll(pointerEventData, raycastResults);

            foreach (var raycastResult in raycastResults)
            {
                ExecuteEvents.Execute(raycastResult.gameObject, new BaseEventData(eventSystem), ExecuteEvents.submitHandler);
            }
        }
    }
}

VRRayCaster.cs

using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
using Zenject;

namespace FrameSynthesis.XR.UnityUI
{
    public class VRRayCaster : BaseRaycaster
    {
        [Inject] ICameraRig cameraRig;

        const float MaxDistance = 0.1f;

        Canvas canvas;

        public override Camera eventCamera => canvas.worldCamera != null ? canvas.worldCamera : Camera.main;

        protected override void Awake()
        {
            canvas = GetComponent<Canvas>();
        }

        public override void Raycast(PointerEventData eventData, List<RaycastResult> resultAppendList)
        {
            var rightHandTransform = cameraRig.GetTransform(TrackingPoint.RightHand);

            var ray = new Ray(rightHandTransform.position, rightHandTransform.forward);

            var graphics = GraphicRegistry.GetGraphicsForCanvas(canvas).ToList();
            foreach (var graphic in graphics)
            {
                if (!IsRectTransformHit(graphic.rectTransform, ray, MaxDistance))
                    continue;

                resultAppendList.Add(new RaycastResult
                {
                    gameObject = graphic.gameObject,
                });
            }
        }

        static bool IsRectTransformHit(RectTransform rectTransform, Ray ray, float maxDistance)
        {
            var corners = new Vector3[4];
            rectTransform.GetWorldCorners(corners);
            
            var plane = new Plane(corners[0], corners[1], corners[2]);
            return plane.Raycast(ray, out var enter) && enter < maxDistance;
        }
    }
}