Sell rental and buy again for tax savings?

I had a primary residence with no mortgage which became a rental. My current primary residence has a mortgage. As understand it, borrowing against the rental to pay the personal mortgage makes the interest non deductible.

It feels like a penalty because I aggressively paid off my mortgage fully before buying another home. Realistically it appears selling the rental and rebuying another immediately could the most tax efficient plan for the long term, even after all the fees with a 25 year horizon.

I’m currently using
1)the smith maneuver
2)buying RRSPs
3)paying rental expenses with a LOC and paying the value on my mortgage

Are there any tax strategies other than the ones I’m already using?