The issue of whether a third party witness bystander could or could not see Jesus is not really a big issue that Apologists (or Skeptics) emphasize because the Bible doesn't give an explicit, open answer on that topic.
More like they don't talk about it because they don't know what to do with it.
We don't have a case in the pre-Pentecost appearances where (A) Jesus shows up for a believer witness and a third party standing nearby does not see Jesus, or alternately, (B) Jesus shows up and a large crowd explicitly including hostile witnesses or nonbelievers do see Jesus. In Matthew's Gospel, the soldiers see an angel who has a sword and it practically makes them faint.
15 Now when the attendant of the man of God had risen early and gone out, behold, an army with horses and chariots was circling the city. And his servant said to him, “Alas, my master! What shall we do?” 16 So he answered, “Do not fear, for those who are with us are more than those who are with them.” 17 Then Elisha prayed and said, “O Lord, I pray,
open his eyes that he may see.” And the Lord opened the servant’s eyes and he saw; and behold, the mountain was full of horses and chariots of fire all around Elisha. 18 When they came down to him, Elisha prayed to the Lord and said, “Strike this people with blindness, I pray.” So He struck them with blindness according to the word of Elisha. 19 Then Elisha said to them, “This is not the way, nor is this the city; follow me and I will bring you to the man whom you seek.” And he brought them to Samaria.
2 Kings 6
15 While they were talking and discussing, Jesus Himself approached and
began traveling with them. 16 But
their eyes were prevented from recognizing Him...... 28 And they approached the village where they were going, and He acted as though He were going farther. 29 But they urged Him, saying, “Stay with us, for it is getting toward evening, and the day is now nearly over.” So He went in to stay with them. 30 When He had reclined at the table with them, He took the bread and blessed it, and breaking it, He began giving it to them. 31
Then their eyes were opened and they recognized Him; and He vanished from their sight.
Luke 24
Matthew's Gospel narrates the angel as having descended from heaven. There is the story of the 500 witnesses, but it doesn't specify whether it included nonbelievers, or even give any more information about it. We can guess that it may have been the same appearance as the one in Matthew's Gospel where Jesus appears on a Mount. I suppose that hypothetically it could have been a confusion with one of Jesus' meetings with 500 people by the Sea of Galilee where he had the miracle with loaves and fishes, but the NT presents those as separate incidents.
In Acts, Paul's traveling companions see a light, and Paul alone hears a voice that he ascribes to Christ. To give an interfaith comparison, in major Islamic writings, there is an episode where Mohammed claims to see an angel, and his wife (or companion woman, I forget), comments that Mohammed sees what she does not see.
Nonetheless, theologians occasionally address in passing the issue of whether the resurrected Jesus could have been or was seen by bystanders, and they give opposing answers on the question.
And they do this because they do not know God needs to give us eyes to see and He blinds the unbelieving so that they cannot.