We have an area that required cutting a lot of holes for electrical updates. It was originally painted (we now know) in oil based paint. They drywall tape and compound we have now doesn’t stick to this? Is there an easy solution?
Its 1300 s/f of space, so painting it all before the patchwork is complete in conversion primer seems rather unappealing!
Wiping down the perimeter of the patches, where the drywall compound will be applied with an alcohol based product, such as denatured alcohol or another type of solvent may soften the oil based paint enough to allow the compound to adhere.
Another method would be the use of a small palm sander with medium grit paper to roughen up the oil based paints surface.
The best way to solve the issue is the latex based primer on the areas to be patched. Latex over enamel will normally work, not the other way around. Although you have expressed hesitation in priming the entire surface with a strong latex primer, this would be the best method of solving the issues.