BLE write doesn't work after requestMTU

I am working on an app that Bluetooth LE feature, thus requires the plugin https://ionicframework.com/docs/v3/native/ble/ , the app works fine if i dont request MTU. The procedure is :

  1. Select a device from the list using scan() method.
  2. Connect to device using the device id received from scanning.
  3. On success callback from this.ble.connect, when device is connected, request MTU size using this.ble.requestMtu()
  4. write data to ble device using this.ble.write()

If i dont request MTU in third step, everything works fine, but per frame, i can send around 20bytes of data. My data is usually of size 4500bytes.
Sending lots of packets reduces the pace, so to speed up, i need to request higher MTU size.

on requestMTU, i get a success callback with response OK, but after that, i can’t write any data, neither it reaches the peripheral, nor i get any error or success callbacks for that.

Any possible lead on how to solve the issue is appreciated.

Devices used : OnePlus 6 with android 9