Whatsapp promotional msgs, multiple msgs at once.

I need an Android app. I already have a design for it, I just need it to be built.

I will give the wireframes, basic designs but need good quality code and stable functionality.
Expect it to be completed in 2 weeks maximum.
I am also an Android Developer, so I'll be moderating the code and functionality. Don't have time to develop this so looking for freelancer.

Refer this app for what I want exactly :
https://play.google.com/store/apps/details?id=com.invotech.whatspromo

Just check the main features like Send multiple msgs, Create and select template, import from excel.
Just these features, login splash, refer earn settings etc not needed at all.

so overall:
user can enter multiple numbers, select template of needed, click on send to send msgs on whatsapp
and
create contact groups (add contacts from contact list or manually), select that group and send message.

message report, how many sent, how many not available on WhatsApp.

I repeat UI is not that important but functionality should be super stable.
portrait mode only support, sdk 21 min to android 11 support.

language: kotlin only