As per
https://www.canadavisa.com/canada-i...ds/can-i-add-work-experience-post-ita.609026/ you can normally add it in personal history.
But this part, "using a VPN although I was supposed to work remotely from my home country only" is a bit troublesome.
At a guess, I'd speculate that you're still okay to include it in your personal history, as per
https://www.canadavisa.com/canada-i...al-for-remote-foreign-work-experience.818120/ it's trouble to count this as foreign work experience (since you were physically present in Canada while working) but also trouble to count this as Canadian work experience (since it's remote work for a foreign employer - presumably no impact to Canadian labour market and all that). So you might not be able to gain any points at all for this work experience - but since you just want to add it to personal history, instead of work history, that's not an issue.
What will you do if IRCC calls your employer and lets slip that you were living in Canada at the time? (Though my understanding is that this is more common for work history where you are counting on the points for that work experience, and it's unlikely to happen if you just add it to personal history.)