I would like to suggest the Do 217 E-2/R5 which was one experimental mounting of an 30mm Mk 101 in sayed Do 217 E-2 which is allready found in game, so i leave it open to the Devs wether its an Modification for the current Do 217 E-2 (like with other planes like the Bf 110s or Hs 129 B-2) or a copy pasted with the gun, cince it is just the change of the Mg 151/20 to the Mk 101 and a new on/off switch with ammo status light. Nothing else.
It could be placed at a lower Br with a more limited Bomb layout for a greater focus on CAS/Air supiority Destroyer.
Why it was made and for what? In 1942 the need for more effecive Anti ground, air and sea planes was growing and different attempts on different planes such as the Bf 110, He 115 and He 177 were tryed. The Do 217 E-2/R5 was also one of them. It was improved by switching out the Mg 151/20 with the 30mm Mk 101, but it seems cince it was left at 1 conversion that it didnt achive the wanted results, but in game it certainly will.
Why i would like to see it in game? Because the Do 217 is a nice plane, there are allready a couple of different versions in game, but not with such a powerfull cannon, which currently in game is only on the Bf 110 C-6 (which is an Event vehicle).
Performance wise it will be identical to the normal allready in game Do 217 E-2 just instead of the 20mm Mg 151/20 it has an 30mm Mk 101, so for the overall performance here is the Wiki link. Do 217 E-2 - War Thunder Wiki
The Mk 101 is also allready found in game MK 101 (30 mm) - War Thunder Wiki
30mm 260 rpm 90rpg.
(With the exception that the I-T round currently is wrong at it has only 2mm instead of 58mm penetration (its the Pzbrsprgr. L’Spur (AphecbcI-T))
Kampfflugzeuge und Aufklärer Entwicklung, Produktion, Einsatz und zeitgeschichtliche Rahmenbedingungen von 1935 bis heute
Weltluftfahrt Band 15
Dornier Do 217-317-417 An Operational History