@Freyrs_storiesI write on Windows (also in a VM, but it's a Windows VM) using Scrivener, so I had nothing to contribute on your base topic.
On the hypervisor topic, though, I can contribute some thoughts. First question: what sort of leaks are you concerned about? Someone getting the disk(s) from the hypervisor host and looking for leaks, or are you concerned with network attacks, etc?
First thought is that pretty much anything is at risk if it's seized while up and running, encrypted partitions mounted, etc. So it doesn't really matter what you host it on - if it's running, there are a lot of points of attack. So, my thoughts below are more about data at rest.
Windows as a host is probably safest against physical-disk attacks if you put everything related to the VM on an encrypted disk. However, if you disable all memory checkpointing, neither Hyper-V nor VMWare should have much in the way of leaks. Remember that Hyper-V is common in datacenter use where leaks are a Very Bad Thing. You do have to worry about the underlying Windows being at risk for malware attacks, but that puts both at equal risk.
The other option is to take a bare metal machine, run VMWare ESXi on it, and build your VMs on that. ESXi has a very limited attack surface compared to Windows (and you can easily firewall it away from the Internet without blocking VMs from reaching the Internet). Your data at rest should be as secure as the guest OS makes it (e.g. if your guest OS is running encryption, your data's encrypted). ESXi is much less likely to leak memory contents.
The learning curve is higher, but it's not that bad.
ESXi is free as in beer for any system the vast majority of people are likely to have at home. You need a license, but licenses are free and easy to get. VCenter is NOT. However, you can do an awful lot with ESXi.
If you want a free software alternative, look at Proxmox. I've used ESXi for years, but even as a raw newbie I found it much easier to use than Proxmox -- but Proxmox works fine, is open source, and isn't that hard to learn to set up.
I have an ESXi box running a number of VMs (file serving, local certificate authority, backups, Plex until recently, downloads, etc) and Proxmox running my router (OpenWrt x86 - virtualization makes it MUCH easier to do updates with minimal risk of crashing my home network). My router is on a tiny, cheap x86 box with network hardware that ESXi doesn't support, or I'd run ESXi there, too.
It's easy to get to the ESXi guests with Windows Remote Desktop, vnc, or X Windows. VMware also provides a very capable free-as-in-beer client; you can pop up a console in a browser window, too, but it won't perform as well.
