These random "good" night of sleep are killing me

I know sleep is so so variable for kiddo in their first years of life, let alone the first 6 months of it but these random nights where she sleeps better (I'm talking 2.5hr, give back paci, then another 2.5 hour and then up hourly from there so not great but better) give me so much false hope.

I know, try not to have expectations but when she slept 5 hours in her side car crib (which she literally has not done in 2.5 months) and not next to me slapping me in the face from her waking every cycle every 45-60 min, I get a little too hopefully.

"Maybe we are turning a corner? Maybe the extra half oz of cereal helped? Let me go through in detail the entire day to see what we did different to make this happen!"

The answer, I did nothing that different to help. She just....slept. and the next night. She didn't.

She will be 6 months in 9 days, but for almost 4 of those months she has rarely slept more than an hour ish at a time. Co sleeping has helped, we have her on an age appropriate schedule (10.5 hours wake, 2.5-3hr sleep), we keep her active during the day but she just doesn't sleep. It's almost easier when I don't get these good night because I'm so let down the following despite knowing I'm doing this to myself.

I know it will get better but that magic one night won't be it.