What's the best German bomber to use for researching the Arado Ar234, I am currently using the Ju188

I am around 50k points away from the Arado Ar234 but I am disappointed at the poor survival ability of the Ju 188 because of the bad gunner layout. What’s the best bomber to get in rank IV? I am considering buying the he-177, i currently have 465k

get he 177 for the rp boost and extra rp from modifications