That may be part of the problem. To install Manjaro as UEFI the Installer medium (in your case Ventoy) must also boot as UEFI. See [HowTo] Create a Ventoy USB to launch Manjaro (and other) ISO’s.
It’s possible to inadvertantly create a hybrid booting system which is booting similar to MBR, but using a GPT partitioning scheme. Whether that’s the case here, I can’t say.
When installing Manjaro as UEFI using Calamares (the Manjaro installer) an $ESP is created on the Manjaro disk (usually the first partition) - yours is absent, as you have shown by way of the image you posted.
Your Windows version on nvme1n1 appears to be booting as UEFI (presumed by virtue of an $ESP being on your Windows disk). The second Windows installation (on sda) is harder to guage, but it looks like both Windows are sharing the one $ESP.
Never use fsck on an M$ NTFS file system. There is only one reliable tool for checking/repairing NTFS - Microsoft’s own tool chkdsk - from an elevated command prompt run:
chkdsk /f c:
Please see [Primer] NTFS on Linux.
Your existing $ESP (on the Windows disk) was extrapolated from the inxi output you finally gave us. As mentioned, the disk you have installed Manjaro to - the same disk as the screenshot you gave us - has no $ESP at all.
“There are none so blind as those who will not see” 
A famous quote from some historical figure; maybe it was an 
who can say?!
Most of this was more or less informational; I’m no closer to understanding precisely what the issue is.
However;
It seems apparent there are inconsistencies with the way you have your system(s) setup. If it were me, I’d consider doing just that “starting from scratch” - it’s certainly faster.
I’ll note that if you are likely to do that anyway, it would also save a lot of potentially wasted time and effort on the part of those wishing to help.
Let us know your plans.
Regards.