I'd rather do the opposite, and parlay, and only risk 1 unit for a chance to win 8. The odds of winning a parlay is the same.

Worse case for 8 losses in a row with Martingale 1-2-4 progression for 8 rounds is -56 units

Worse case for 8 losses in a row with parlay positive progression is -8 units

Best case if you win 8 rounds in a row with Martingale is 1 unit a round, so in 8 rounds you can only win 8 units

Best case if you win 8 rounds in a row on Parlay is 64 units

So in 8 rounds with a negative progression the most you can win is only 8 units...but you're risking up to 56 units of your own money.

But with the parlay bet, you can win up to 64 units best case scenerio, but you're risking only 8 units of your own money.

Also, you said after 2 losses raise wager so this will make potential losses way steeper than the examples I just gave.

The odds are the same. Got to look at risk vs reward