Segment by economics
Use custom labels in the feed for margin tier or performance tier, then build campaigns around those labels. Now budget can follow profit rather than spreading uniformly.
Separate the proven from the unproven
Best sellers get their own campaign and room to scale. Untested products get a capped discovery campaign where losses are bounded.
Exclude, do not duplicate
If two campaigns can serve the same product, they compete and you pay for it. Every product should have exactly one home.
What not to do
A campaign per product in a large catalogue. It feels like control and it starves every campaign of the data it needs.