Employee vs Contract

I am currently contract at $55/hr, working 12 hr days 6 days a week. I use my truck (personal) which makes $110/day (company I work for provides fuel) and get paid $175/day loa. I pay myself $4000/month salary to prove personal income + $200/day loa since it’s tax free (my company collects 5% gst). I also pay my wife $2000/month salary to do the bookkeeping.

Employee wages vary by company but most pay $37-44/hr and dont provide benefits with the exception of union which pays $54/hr plus benefits and pension, total package ~$70/hr. Employees can use their own truck ($110/day) and get loa. Union provides trucks and pays loa or provides camp.

I have a young family with 3 kids, 5 and under. We bought our current house 6 years ago when I was an employee.

We want to buy a rental property and start building our passive income (I currently invest $3500/month in large cap ETFs) but I have heard being self employed can make it difficult to get a mortgage.

Most people I talk to seem to think being contract is better than employee because of the write offs and tax benefits. But I am leaning toward taking a union position to enjoy having benefits for my family and making it easier to get a mortgage.

Should I stay contract and explore buying a rental with my corporation? Or try to get a personal mortgage? (I have only been contract for 6 months) Should I go back to union work and get a regular job that the bank likes to see?

Edit: I’m in Canada