I mean it dosn’t even get any bombs and the only other armament is a pair of MG17s, and the 37mm cannons have no HE filler in them, so I’d say BR1 is perfectly fine for it, at BR2 it probably would be unused because stukas with bombs are at the same BR, and bombs can also kill infantry.
If that is all the plane got then it would need to be BR 0 as even in BR 1 it would be terrible.
The gun ( also found on the BF110-G2 ) is still bugged and cant pen shit better armored than the A13 and then is still stuck with only solid shot so even then you might just kill 1 or 2 tankers.
And if a plane has only anti tank cannons then it is very useless should no tank respawn to replace the initial tank you where hunting meaning you are stuck circling the sky or need to suicide.