No. The Windows bootloader should not be deleted. However, as it’s a new installation you might consider extending the ESP to 300MB, for example, after you install Windows (if you can find a safe way to do that). Then install Manjaro, confident in knowing enough space is available.
Please take careful note of the points raised by @zhongsiu, as they are also important to ensure a successful installation.
You might also like to read through Multiboot Windows and Linux on Separate Disks → Skip past the separate disks tutorial part, and read everything under Important Caveats.
I hope this helps. Cheers.
Not according to this. Some conflicting information, methinks.
