I don't know warm season grass much, but when it comes to seed 3+ months is too long. Unfortunately, that seed is likely dead.

Watering 1x per week works for well established lawns - not for seed. I'm pretty confident that was your problem. You have to water seed 2-3x per DAY. It must stay moist at all times. When it has germinated, you can slowly, as it matures, back off to 1 time per week - preferably 1" of water.

I don't know if Bahia is specifically hard to grow, but you will probably have to give it it's fair chance with plenty of moisture. There are other factors in how well the seeds sprout, but water seems to be a big one. A seed needs (1) water, (2) oxygen, and (3) warmth to grow. My understanding is that if it doesn't have warmth, it will wait to grow. Oxygen is in the soil typically, unless the soil is super compacted, but you would notice that because the rest of your yard likely wouldn't grow either.

Hope this helps.