Another tire won’t do squat for your air loss situation.
Ignoring the possibility of a leak due to a physical conduit, e.g. puncture, leaky valve etc. the easiest fix to try is to shop around for the heaviest tube you can find in that dimension. Thicker tube = less air lost through the rubber.
If you feel up to the task, you can try a Tubeless conversion. On tires with thick sidewalls, you may lose less air through the tire than through the tube.