i had same issue last month what fixed it for me: i stopped chasing only high DA, started checking real traffic too. sites with real traffic index way faster i was doing too much exact anchor, switched to like 70% branded/generic now i submit every guest post in GSC + build 2-3 quick tier2 links (reddit + medium) and they index in 24hi run a small network of 12 sites (tech/business/health etc) da 22-50 with organic traffic, thats how i test. worked for me after lot of fails lol if u want i can share my checklist