Suicide Squad was awful but it didn't bomb. It would be middle of the pack for Marvel, ahead of 2/3 of the Iron Mans amongst others.
It can't be that bad, but I don't think it's doing more than the $325m Suicide Squad did domestically. Deadpool did $363m and Deadpool 2 did $324m and I think Joker will do $300m or just under.
Of course Suicide Squad did big business abroad, and I'd be amazed if Joker did that.