Hope this is accurate.
“However, recent news suggests that Ukrainians developed ballistic missiles with a range of more than 400 km and have already started targeting critical supply lines in Crimea.”
Developed(with help?) or given. Imagine all that is donated is not announced and hope that long range munitions is part of that. Ukraine will need boat loads of these to strike Russia in mass at time of offensive to disrupt logistics, troop concentrations, infrastructure. Once Ukraine launched their offensive they will have exposed flanks that need to be protected. One way is to make the Russian forces in the area confused and deprived of munitions, leadership, and safe haven. Though the Russians have not been performing well they still have numbers, numbers don’t matter much if they are routed like Kharkiv.