Not really.

In the Russian case: average BTG went into the battle with about 800 troops. AFAIK, BTGs of 1,000(+) troops were rare. Meanwhile, most are…

Not really. Most of Ukrainian 'squares' are brigades, with 2,000-3,000 troops. Many are depleted by now, but others might have been reinforced by elements from other units.

In the Russian case: average BTG went into the battle with about 800 troops. AFAIK, BTGs of 1,000(+) troops were rare. Meanwhile, most are down to 400-500 troops (or even less). Indee…