Ready to test out Delta Green. Give me your best scenarios, ranked from easiest to hardest to run!

I’m looking to dip my toes into Delta Green and test the system out with my group. I’m already an averagely experienced Keeper in Call of Cthulhu and have run quite a few other systems, but I want to make sure I get a good feel for the unique mechanics and vibe of DG.

I’m hoping you can help me put together a short list or "campaign progression" of cool scenarios to run. Specifically, I’m looking for scenarios arranged in an escalating level of difficulty for the Handler. I'd love to start with something that's relatively easy to prep and run to get my bearings, and then slowly ramp up the mechanical or narrative complexity as I get more comfortable with the system.

• My players are completely okay with any kind of content or heavy themes.
• My only request is that scenarios that are genuinely fun and engaging.
• I’m totally open to official published operations, Shotgun Scenarios, or highly-rated fan-made content.

What scenarios would you string together for a Handler just starting their career in the Program? Thanks in advance for the help!