2004 Red Triangle of Death / CEL / more issues

2004 102,000 miles, was my grandmothers vehicle which was used all locally for first 16 years of its life (75k) , i tacked on the rest since 2020. - Maintenance was standard, Routine and up to date.
All of a sudden : Triangle light, Check Engine light, and Info (!) light on the dash. Hybrid battery on display will drain rapidly just sitting in park, in a matter of 5 minutes it goes full green to one bar purple.
I checked the codes : P1121 - Replaced with OEM parts, and retopped off OEM Coolant , P1116 - Coolant Temperature Sensor - yet to do repair as i wanted to ask you all first what to do.
I clear the codes, and they return shortly after , i then experience moments of no throttle response ( vehicle still fully powered just not moving) once i come to a stop and wait....re-accelerate and it will do so? very odd.

so i'm not getting a code that would point to the battery being the issues directly, which lead me to thinking it was the hybrid battery fan, i went back there and cleaned it up (wasn't bad at all), while back there i gave the Battery a touch and good lord was it HOT! so is this an overheating issue causing the battery to act up, or is this a failure in the battery itself.
any help is appreciated, i'm looking at a Full Replacement of Hybrid Battery ($1,499 + tax for a fully warrantied)
or the possibility of Fixing the underlying issue at a more not insane price tag lol

thanks in advance gents