Renewing soon - dump into mortgage or keep investing?

I’ve finally reached a point where my registered accounts are all maxed out. Value is around $500k for these.

For context: I’m 33, have one newborn and wife is planning to stay at home. Income of 300-400k (sales, fluctuates). House valued at 1.5M, $820k mortgage remaining at 1.9%. Renewal in September, assuming it’ll be around the 4% mark.

I do write off some expenses related to the home/auto since I am a commissioned employee.

I have an extra $80k in non-registered which I’ve been DCAing regularly.

I keep thinking whether I should just pay down the mortgage, or continue to invest.

Plan is to be financially independent by 50.

Thoughts on my situation?