>>Why it took this long is a good question.
It seems pretty simple. There was a contract and Ukraine was demonstrating that they follow the law, war or no war. IMO this'll be important once the war is over and companies are looking for reasons why they should invest. A past history of sticking to a contract in spite of a war can make investors more comfortable putting money in Ukraine.

That said, my understanding is that up till now Transnistria has been getting gas effectively for free as Gazprom has been billing Moldova for it. Moldova refuses to pay so Gasprom considers that to be an accumulating debt. Transnistria has a gas-fired power plant and they've been selling electricity to Moldova so they've been getting income from this 'free' gas.
Moldova has offered Transnistria gas at market rate (what they pay for it), but that's the sticking point. I think if they offered it for free, Transnistria would accept - but why should they do that?