Manjaro not booting after removing a kernel and adding a new one

Hi @samya-ryz5,
I suggest you to try the fallback initramfs option first, to see what happen.
You can also read the following post in order to reinstall the kernel, it is always a good practice not to remove and install the kernels at the same time. You should install the new one, reboot and then remove the old one. Perhaps, you could consider to keep both kernels whether you have problems with one of them.
If you have no response on the fallback optiion try to login from the tty with Ctrl+Alt+F2, login with your name and password and install the kernel you remove and the new one again.

Manjaro Kernels - Manjaro

Here is another post whether you could boot only in fallback mode, which could also help to find the solution.
Manjaro only boots in initramfs-fallback - #15 by Berserk

Hope this help, regards