Lucky for you I got a handy dandy spreadsheet that someone made for the last humble bundle release. But, if you ignore the color coding, it gives you a perfect reading order. Good jumping on points are Escalation, All Hail Megatron, and Death of Optimus Prime/MTMTE/RID. Jalaguy's March 2019 Humble Bundle reading guide
If you wanna start from the beginning, do Megatron Origin. Otherwise, All Hail Megatron and DoOP are pretty good starting points too.
Publication order: 2005 IDW continuity - Transformers Wiki Always go for the publication order, because that's how aby given continuity naturaly developes.
Personally, I’d suggest that you skip the old IDW run altogether (a lot of people love it; I find it generally confusing) and start with the new comic from issue number 1.