Standard L4 blitzing. You can run 3-4 burners in quick succession - each netting you around 20-25m ISK plus drops. You can run all the regular and team burners in a unified Nergal fit. So once you have the skills/ship/modules, it earns very well.
Every now and then you’ll need to pause and run some regular missions to bring your standings back up (if you’re declining a lot of missions to just focus on burners). Yesterday I played for 45min (no declines) and netted ~225m ISK (after LP conversion).
Abyssals can earn a lot more - but the ships and implants are more expensive and there’s a lot more associated risk.