Hi Maehhh,
Scheduled maintenance is not the issue, Vedneyev engines are very reliable and strong. But forget about going to the airfield, pull out the plane sit in, fire it up the engine and go.
You must drain lower cylinders from all gravity accumulated oil, you have draining plugs or draining caps to remove, . turning the prop on a radial engine requires a feel and knowledge do be done properly, hydraulic lock can come in many forms, as resistance to turning , even without resistance oil accumulated con seep back inside intake manifolds if intake valve opens and be sucked in after engine fires ( Tailwheels Yaks and Sukhois, are sitting tail low and bottom intake manifolds are below intake valves).
Then the air system requires a spare air bottle and manifold for recharge in case of too many missed starts, Fuel priming for start has to be mastered and understood to successfully start engine especially when warm.
Engine management notably cylinder temperatures require constant monitoring in flight. 30 seconds at take off power with gills left closed can result in cooking the engine.
Nothing serious but it requires attention and time, then better have some manual skills to change high tension wirings, oil and fuel lines, tyres and brakes, spark plugs..get trained and be ready if you don't want to get stuck and grounded. Many things you can do yourself, may be time consuming but worth it; if you have to rely on a technician, then be prepared to disburse $$$$$$$.
No big deal if you are mechanically inclined and have some manual skills and some training, after all owning and driving a Norton or an Harley or a Guzzi in the sixties this was daily bread !!