Kurt I've looked the load games and Entente player had made serious mistakes in initial rounds like not rolling in Northern Mexico with USA cavalries in round 1, USA atlantic navy, Buying England Factory instead of 5 sub/fighter in London, allowing Germany to stay in English Channel, Buying Volgograd factory too early instead of trying to recapture Warsaw, not trying to capture Switzerland in initial rounds with Italian cavalries, not staying in Milan. Had Entente done somethings differently game wouldn't last longer than 15 rounds.
Any game can last even more with such a defensive playstyle. But the most critic rounds are indeed the initial round between 1 and 5.
With your tech system, Germany will never have Late fighter in initial rounds and immiadetaly lost its navy and with Scandinavian incomes Entente will start heavily outproduce Centrals.
Lack of Creeping Barrage/armour/industry in initial rounds is huge punishment for Centrals. It will significantly weakened Centrals. There is no reason for Entente to fear offensive techs/units of Central powers. Centrals have absolutely zero chance to take Paris even with early industry tech which is nerfed.
No industry and no late fighter for Germany means having almost zero chance to take Marseille,Piedmont, Losing Scnadinavia and delaying Austria pushing Russia, Italy. And finally guaranteeing to keep Northern Italy/Southern France with USA reinforcements via Morocco,Spain.