Unfortunatelly I couldn’t fix the problem and decided to do a full wipe and start again after backing up what I needed. However I do not want this post to be completely useless so below I’ll link tutorial on properly installing Windows and Manjaro in Dual Boot and repairing the grub bootloader
Windows 10 and Manjaro Dual Boot install: [root tip] Dual boot Manjaro and Windows - #2 by homerhomer
Dealing with grub bootloader: Using livecd v17.0.1 (and above) as grub to boot OS with broken bootloader - Tutorials - Manjaro Linux Forum