Admittedly, I've not used my phone much for the past couple weeks, but my stats are as follows:
65% battery remaining, 9d 0h 56m 9s on battery, Phone Idle 25%, Wi-Fi 24%, Cell standby 16%, Screen 13% (3h 13m 39s), etc. Are you using auto brightness or set brightness?
I also use CM Browser in favor of Chrome (tried different ones and like this one the most)--not sure if it's better for battery life, and I don't use Tapatalk for any forums, though I do read at least 2 forums frequently.
I should note I'm on Cyanogen 11.0, Android 4.4.4--have not used a custom ROM for this particular phone nor been interested in upgrading to the new OS, since this one has been great and stable. You are saying that you've played with other ROMs--does that mean you're not on stock anymore? If so, any number of things could be causing your issues, and you'd have to troubleshoot by specific ROM.
Still not sure how you are only getting under 3 hours of use. I wouldn't call it "screen time", because you can have the screen on and not be doing anything and you can be playing a CPU-intensive game the whole time--very different battery drain profile.