Kotlin - app crashing with complex calculations, would appreciate help

[atbeat]

class MainActivity : AppCompatActivity() {

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

        val age = binding.etAge.text
        binding.tvSex.text
        val weight = binding.etWeight.text
        val height = binding.etHeight.text
        val creatinine = binding.etCreatinine.text

        val btnCalculate = findViewById<Button>(R.id.btnCalculate)
        val btnReset = findViewById<Button>(R.id.btnReset)

        val female = binding.rbFemale

        val pounds = binding.rbPounds

        val inches = binding.rbInches
        val mg = binding.rbMg

        var tvBMIv: Any?
        var tvBSAv: Any?
        var tvCrClv: Any?
        var tvEGFRv: Any?
        var tvGFRv: Any? = Any()

        val tvBMI = binding.tvBMIv
        val tvBSA = binding.tvBSAv
        val tvClearance = binding.tvCrclv
        val tveGFR = binding.tvEGFRv
        val tvGFR = binding.tvGFRv



        btnCalculate.setOnClickListener {

            //hideKeyboard()

            // Conversions to SI units

            val weightKg: Any?
            val heightCm: Any?
            val creatumol: Any?


            if ((age.isNullOrBlank()) || (weight.isNullOrBlank()) || (height.isNullOrBlank()) || (creatinine.isNullOrBlank())) {
                Toast.makeText(
                    this,
                    "Please assure all values are entered!",
                    Toast.LENGTH_LONG
                ).show()
            }

            weightKg = if (pounds.isChecked) {
                weight.toString().toDouble() / 2.2
            } else {
                weight
            }

            heightCm = if (inches.isChecked) {
                height.toString().toDouble() * 2.54
            } else {
                height
            }

            creatumol = if (mg.isChecked) {
                creatinine.toString().toDouble() * 88.4
            } else {
                creatinine
            }


            tvBMIv = String.format(
                "%.2f",
                (weightKg.toString().toDouble() / (heightCm.toString().toDouble() / 100).pow(2)
                    .toString().toDouble()).toString()
            )
            tvBMI.text = tvBMIv as String
            
            tvBSAv = String.format("%.2f",(0.20247 * (heightCm.toString().toDouble()/100).pow(0.725) * (weightKg.toString().toDouble().pow(0.425))).toString())
                tvBSA.text = tvBSAv as String

            tvCrClv = if (female.isChecked) {
                String.format("%.2f", ((140 - age.toString().toDouble()) * weightKg.toString().toDouble() / creatumol.toString().toDouble()) * 1.04)
            } else {
                String.format("%.2f", ((140 - age.toString().toDouble()) * weightKg.toString()
                    .toDouble() / creatumol.toString().toDouble()) * 1.23)
            }
                tvClearance.text = tvCrClv as String

            tvEGFRv = if (female.isChecked) {
                String.format("%.2f",(144 * (creatumol.toString().toDouble() / 61.88 * (0.993).pow(age.toString().toDouble()))).toString())
            } else {
                String.format("%.2f", (144 * (creatumol.toString().toDouble() / 79.56.toString()
                    .toDouble()) * (0.993).pow(age.toString().toDouble())).toString())
            }
                tveGFR.text = tvEGFRv as String

            tvGFRv = String.format("%.2f", (tvEGFRv.toString().toDouble()/1.73) * tvBSAv.toString().toDouble())
        }
                tvGFR.text = tvGFRv as String

            btnReset.setOnClickListener {
                age.clear()
                weight.clear()
                height.clear()
                tvBMI.text = ""
                tvBSA.text = ""
                tvClearance.text = ""
                tveGFR.text = ""
                tvGFR.text = ""

                

        }
    }


}

Could this be because I am performing multiple and complex calculations with one button click. Code is written using Kotlin. Android studio doesn’t give any errors in code in either activity_main.xml or manifest.kt files. If I comment off the code after “Calculate button”, the app is working up to that level, so not clear where the issue is. Thanks