How do I start running again after two years off?
Cap it by time, not distance, and keep the first three weeks conversational. Injury on a return almost always comes from pace, not volume, and the tissues that need adapting take longer than the fitness that returns first.
Can I make progress with bodyweight only?
For a long while, yes, by changing leverage rather than adding weight: elevate the feet, slow the eccentric, move toward single-limb versions. Progress stalls eventually on pulling movements, which is where something to hang from becomes the one purchase worth making.
Is there a simpler version that gets most of the benefit?
Yes: do the first step, skip the automation, and revisit in a month. Most of the value is in the first step, and most of the cost is in making it repeatable before you know it is right.