how do i use Intent method

I am trying to use an intent in an onClick method,the intent does work...but it doesn't want to change to the other activity im looking everywhere but nothing seems wrong. note:i dont know why FragmentPagerAdapter is deprecated

code:

MainActivity.kt

    class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding
    private lateinit var viewModel: MainViewModel
    private lateinit var  adapter: UserAdapter

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        adapter = UserAdapter()
        adapter.notifyDataSetChanged()

        adapter.setOnItemClickCallback(object : UserAdapter.OnItemClickCallback{
            override fun onItemClicked(data: User) {
                Intent(this@MainActivity, DetailUserActivity::class.java).also{
                    intent.putExtra(DetailUserActivity.EXTRA_USERNAME, data.login)
                    startActivity(intent)
                }
            }
        })
        viewModel= ViewModelProvider(this, ViewModelProvider.NewInstanceFactory())[MainViewModel::class.java]

        binding.apply {
            rvUser.layoutManager = LinearLayoutManager ( this@MainActivity)
            rvUser.setHasFixedSize(true)
            rvUser.adapter = adapter

            btnSearch.setOnClickListener{
                searchUser()

            }
            etQuery.setOnKeyListener { _, KeyCode, event ->
                if (event.action == KeyEvent.ACTION_DOWN && KeyCode == KeyEvent.KEYCODE_ENTER){
                    searchUser()
                    return@setOnKeyListener true
                }
                return@setOnKeyListener false
            }
        }

        viewModel.getSearchUsers().observe(this) {
            if (it != null) {
                adapter.setList(it)
                showLoading(false)
            }
        }
    }

    private  fun searchUser(){
        binding.apply {
            val query = etQuery.text.toString()
            if (query.isEmpty()) return
            showLoading(true)
            viewModel.setSearchUsers(query)
        }
    }

    private fun showLoading(state: Boolean){
        if (state){
            binding.progressBar.visibility = View.VISIBLE
            }else{
            binding.progressBar.visibility = View.GONE
        }
    }
}

UserAdapter.kt

    class UserAdapter : RecyclerView.Adapter<UserAdapter.UserViewHolder>() {
    private val list = ArrayList<User>()
    private var onItemClickCallback: OnItemClickCallback? = null
    fun setOnItemClickCallback (onItemClickCallback: OnItemClickCallback){
        this.onItemClickCallback = onItemClickCallback
    }
    fun setList(users: ArrayList<User>){
        list.clear()
        list.addAll(users)
        notifyDataSetChanged()
    }

    inner class  UserViewHolder(private val binding: ItemUserBinding) : RecyclerView.ViewHolder(binding.root){
        fun bind(user: User){
            binding.root.setOnClickListener{
                onItemClickCallback?.onItemClicked(list[adapterPosition])
            }
            binding.apply {
                Glide.with(itemView)
                    .load(user.avatar_url)
                    .transition(DrawableTransitionOptions.withCrossFade())
                    .centerCrop()
                    .into(tvUser)
                tvUsername.text = user.login
            }
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): UserViewHolder {
        val view = ItemUserBinding.inflate(LayoutInflater.from(parent.context), parent, false)
        return UserViewHolder((view))
    }

    override fun onBindViewHolder(holder: UserViewHolder, position: Int) {
        holder.bind(list[position])
    }

    override fun getItemCount(): Int = list.size

    interface OnItemClickCallback{
        fun onItemClicked(data: User)
    }

}

DetailUserAdapter.kt

    class DetailUserViewModel: ViewModel() {
    val user= MutableLiveData<DetailUserResponse>()

    fun setUserDetail(username: String){
        RetrofitClient.apiInstance
            .getUserDetail(username)
            .enqueue(object : Callback<DetailUserResponse>{
                override fun onResponse(
                    call: Call<DetailUserResponse>,
                    response: Response<DetailUserResponse>
                ) {
                    if (response.isSuccessful){
                        user.postValue(response.body())
                    }
                }

                override fun onFailure(call: Call<DetailUserResponse>, t: Throwable) {
                    t.message?.let { Log.d("Failure", it) }
                }

            })
    }

    fun getUserDetail(): LiveData<DetailUserResponse>{
        return user
    }
}

SectionPagerAdapter.kt

    class SectionPagerAdapter(private  val mCtx: Context, fm: FragmentManager) : FragmentPagerAdapter(fm, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT) {
    @StringRes
    private val TAB_TITLES = IntArray(R.string.tab_1)

    override fun getCount(): Int = 2

    override fun getItem(position: Int): Fragment {
        var fragment: Fragment? = null
        when(position){
            0 -> fragment = FollowerFragment()
            1 -> fragment = FollowingFragment()
        }
        return fragment as Fragment
    }

    override fun getPageTitle(position: Int): CharSequence? {
        return mCtx.resources.getString(TAB_TITLES[position])
    }

}