Some dubious versions about
No recommendations other than Inkscape site.
Portable tends to be 32 bit to make more 'universal' although I wonder how many Windows 32 bit installations / Inkscape users are still around.
The question is how portable do you want Inkscape? The 64 bit 7z archive from
https://inkscape.org/release/1.0/platforms/ unpacks and runs from anywhere (caveat, Windows paranoia and AV permitting) but when run first time, same as Gimp, adds a user profile to "yourname"\AppData\Roaming\
If unable to live with that, then a bit of gentle hacking.
Install the 32 portable version from Inkscape (It is the same as the PortableApps.com version)
Replace the 32 bit Inkscape folder with the 64 bit inkscape folder from the 7z archive. Make sure you unpack that with the folder structure ( 7z x inkscape-1.0-x64.7z)
The PortableInkscape.exe launcher is still 32 bit but the application is now 64 bit, with the required environmental variables for a portable version.
Worth a try
A couple of Win10 (VM) screenshots :
https://i.imgur.com/UFH9SsC.jpg