Hey there. If you're looking for highest returns and minimal risk in CAD, there isn't really anywhere else you can go besides TBIL ETFs or HISA ETFs.
Something like CBIL is effectively risk free and carries a yield of 2.58%.
If you're willing to take on a bit more additional risk for a bit more yield, corporate bond ETFs are not a bad idea. However, there is the added element that a bond ETF is not structured identical to a bond. With an individual bond, you buy the bond, receive the coupon payments and get your capital back at maturity. Because these funds contain a multitude of bonds maturing at different times, the price of the fund can fluctuate wildly and there is really no time period where your initial capital is guaranteed.
I know rates are low right now, but ultimately if you want zero risk and maximum return, you'll need to look to short-term government treasuries, which don't really pay all that much right now at 2.6%~