Tried installing with default npm that comes with Node.js LTS (v20.x) and got code 7 error, something to do with node-gyp.
Tried npm preinstall then install which resulted in the same error.
Solution:
Noticed the warning about recent npm packages on MMM-GA wiki (But wiki just said npm 10.x module will work, would like for it to be more specific - a specific version like 10.1.0 has been tested and it works)
Removed MMM-GoogleAssistant git files
Installed npm 10.1.0 (npm install npm@10.1.0)
Ran the commands again starting from git clone
npm install was a success
Just documenting my installation journey as it might be useful for somebody.