Hi Shail,
I don't think this will have a material impact. Usually, if a change at the top is going to impact share price it will do so immediately upon announcement. Furthermore, when its a 'promotion' from within, there is usually less fanfare.
In order for a stock to move on a CEO change, it has to be because there was big underperformance and a transformative outsider is brought in to right the ship. Sure, the wrong CEO can impact share price long-term, but that usually isn't known until its too late.
In terms of Magna itself, it remains a best-in-class auto parts company. It is a Canadian Dividend Aristocrat with a strong history of earnings and revenue growth (pandemic aside) .That being said, its fortunes are tied to the auto industry which can be highly cyclical and volatile. In terms of valuation, the company isn't all that expensive despite the run up in share price. A big reason for this is that the autoparts industry (in Canada) has been chronically undervalued (as compared to US peers) for years due to the uncertainty around Trump's protectionism policies (tariffs, taxes, CUMSA, etc).
Although I don't own it, I do like the company and is one of the best to own in the auto industry. As mentioned however, be prepared for volatility.
Mat