If you're looking for a single KSP2 mod that can do everything that MechJeb did (and still does!) in KSP1, well... you'll need to keep looking. But if you'd like to pull together a sizable fraction of those capabilities and you're willing to split this across a few different mods, then you're in luck!
Flight Plan brings you many of the features and capabilities you might remember from MechJebs Maneuver Planner capability. Flight Plan's core strength is as an aid to help with setting up maneuver nodes to get you where you want to go. With Flight Plan 0.8.0 and K2-D2 0.8.1 you get precision node execution too! Flight Plan integrates seamlessly with both Maneuver Node Controller and K2-D2 and is the perfect complement to all the juicy info you can get from Micro Engineer and Resonant Orbit Calculator!
Maneuver Node Controller can handle any number of maneuver nodes on a single trajectory (well, up to 9, the most the game will support) and enable you to finetune each node! You'll be able to see the quantified details for the orbit that should result from each one, if you can perform a precision node execution...
Fortunately, K2-D2 has you covered for precision node execution, as well as launch and even landing too! (Airless worlds and moons only)
Micro Engineer is the place to go for all the info you're ever likely to want and is highly customizable to your needs! Want more? No problem! Less? Even easier? This thing before that or in whatever order? The world is your oyster, baby! You can customize and tailor the details to any possible need, and break things into smaller windows you're free to move around, just like some of our favorite KSP1 mods.
Now that you've got where you're going, what if you want to set up a complex network of satellites while you're there? Resonant Orbit Calculator to the rescue! No mere slide rule here, this baby packs in the brains of a steely eyed missile man to get you all the info you'll need to set up even the most complex constellation of satellites!
Node Manager Is a library of functions used by both Flight Plan and Maneuver Node Controller, so it's a must as well, though it won't be taking up any of your valuable screen real estate! Node Manager is the quite one running in the background and helping to keep everything going smoothly as you make, edit, and delete nodes to get you where you're going.
You could go flying around space without these, but why would you?