Search bar disappears during scrolling - ios

Question

I've read some Stack OverFlow posts and nothing from there has worked. I have one simple problem that shouldn't be incredibly difficult to solve. I have to stop the search bar from disappearing when scrolling on the tableview that it is attached to.
I have tried:
set the tableview to .plain to make the header view sticky, but that didn't work.
I tried navigationItem.hidesSearchBarWhenScrolling = false, but this may not have worked because searchController.searchBar is set equal to tableView.tableViewHeader.
Here is my viewDidLoad, which should contain the relevant code when this works, if it is indeed possible:
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
tableView.separatorStyle = .none
tableView.backgroundColor = UIColor.init(red: 240/255, green: 246/255, blue: 243/255, alpha: 1)
tableView.register(SearchTableViewCell.self, forCellReuseIdentifier: "SearchTVC")
searchController.searchResultsUpdater = self
searchController.dimsBackgroundDuringPresentation = false
searchController.searchBar.delegate = self
definesPresentationContext = true
navigationController?.navigationBar.isHidden = true
tableView.tableHeaderView = searchController.searchBar
searchController.searchBar.tintColor = .darkGray//UIColor.white
searchController.searchBar.barTintColor = UIColor.convertHexColor(hex: "eaeaea")
navigationItem.hidesSearchBarWhenScrolling = false
searchController.hidesNavigationBarDuringPresentation = false
searchController.searchBar.text = ""
addConstraints()
presentInitialView()
}