So.

Wrote the whole assembly program from scratch.

Checked the output after writing each and every function. 

Always check the registers and program counter if something isn't happening as per your logic.

You can check out the Wokwi simulation and the final Assembly file to see the final results.

Shoutout to Wokwi - It is an amazing simulator and the in built web debugger is a godsend for anyone working with AVR Assembly. I so wish I had this when I was getting sick and tired of working with Proteus simulations for my Bachelor's degree coursework.

But I don't think there would be another time that I would write a whole program in Assembly XD

Why write 450 lines of code when you can get it done in 100 lines?

Efficiency? Maybe.

That said, learning AVR Assembly provided me with a whole new perspective into how an Arduino works.

Now I know how to blink an LED with Ports and Timers :)

(People who made the AVR libraries are geniuses.)