Electric oven trips RCD immediately
It sounds like the high heat damaged the wiring in the oven.
The light bulb being removed would indicate that damaged wire is on the neutral side with it out if you try to turn it on and the rcd holds. The elements probably have a similar issue with damaged insulation.
If I was trying to find this wire damage I would look where the lamp and elements might be close to each other coming through a fitting.
I would look for wire that was overheated and you can probably repair it with high temp fixture wire most ovens use 12 gauge wire for each element but it needs to be high temp fixture wire or it will fail when the oven is heated for any length of time.
I have seen some commercial ovens that used 10 awg 1 time I use high temp “spade” style quick disconnects when the elements have those type of connectors if they use bolt connections I still use high temp crimp rings , standard crimp fittings will not hold up to the heat and current and fail in a short amount of time.  But luckily your RCD has prevented massive arcing and possibly a fire.