As a slight aside I would be very interested to know the size of orders that are being placed in 5.6, 7.62x39 and 7.62x51 ball ammunition - they must be enormous!
You've forgotten 7.62X54R (7.62X53R as the Finns call it on their side of the border). Most Ukrainian machineguns will use this cartridge, it's on the 'suspended' list, and few Western (especially US) companies make this brass / ammo.
7.62x39 / 6.5 Grendel Would be awkward but they’re not exactly common.
7.62X39 is so common and made by so many companies that I'd be surprised if supplies dry up - note, Lapua hasn't suspended it. Americans have been making 6.5 Grendel from it for some time thanks to a shortage of Grendel cases there that predates the war. Size and fireform using either the jammed bullet or false shoulder methods. The trouble is that it doesn't make a great Grendel case thanks to the use of large primers and resulting weaker case-head. Early PPU Grendel brass was LR primed and gained a reputation for short case-life thanks to case-head/primer pocket expansion. (Which is slightly surprising in that the SAAMI MAP is set at only 52,000 psi, and it's said to be important not to exceed that in the dominant US rifle type chambered for the cartridge, the AR-15.)