I agree with Savoir.
I would take the oven
racks, removable burners (not the knobs) etc. and put them in a kitchen trash bag. Take outdoors somewhere, spray the stuff with Easy Off (while still inside the bag), tie the bag up and walk away. Let it sit overnight, and then wash it off, even with a hose initially. Dry with paper towels, and repeat the process with a new trash bag.
Also on Day 1, spray the oven interior
(minus the racks which you have removed), shut the door and walk away. Next morning, wipe out with hot soapy rags, dry with paper towels, and repeat again.
If the stove/oven aren't too bad, you can soak a rag with straight ammonia, wring it out a little, stick it in the oven and (again) leave it overnight. The next day, you will be surprised how much has been loosened. Repeat if necessary. Actually, when we are cruising, I use ammonia to clean our oven instead of dealing with the fumes from Easy Off (yes, I know Easy Off is somewhat less fumy as it was in the dark ages).
If you have a glass cooktop, I use a sponge with a non-scratch scrubby on it (it has to be non-scratch), soak it with hot water
and dish soap, and scrub and wipe. Then dry with a clean kitchen towel. I also carry a very small bottle of glass top stove cleaner in my galley
, and rarely use it but sometimes just a drop comes in handy.
Having had house renters in the past, I find that treating, walking away, and coming back the next day helps gradually loosen everything. My husband (Sunspot Baby on this forum), has a favorite saying: "Incremental Improvement beats postponed perfection" and in this case it's just the ticket.