There is no J-4 in real life, there is only the J-5 (Shenyang J-5 - Wikipedia)
Please change the name
then we should add J-5 then if J-4 and J-5 are seperate
“We” don’t get to add anything.
Gaijin may choose to at some time, but the J-5 is the Chinese version of the Mig-17F, and that isn’t in the USSR tree yet.
They may add the Mif-17F as a type for the USSR, then it’s just a cut and paste job for the J-5…and they are good at that.
Would have been better to read the article properly in the first place tho’, and make the J-5 a proper suggestion.