2008 Prius - 100k Miles - Trying to troubleshoot

Timeline of Events:
I bought a Prius.

The red triangle with an exclamation point, the check engine light, and the VSC light were on.
The check engine codes are: C1241, C1310, P0A80, and P3017.

So far, I have done the following:
Replaced the car battery since it wouldn't start. Now it starts.
Performed a full tune-up: oil change, oil filter, new spark plugs, coolant topped off (need to check if it needs more), and a new air filter.

Before the tune-up, the car would stutter a lot when trying to accelerate. That issue has stopped, but it still has heavy acceleration problems sometimes. I can even floor the gas, and it will stay at the same speed.
Interestingly, before the tune-up, the car was only getting about 20 MPG, but now it’s around 42 MPG. I’m confused because those codes indicate the hybrid battery isn’t functioning properly, yet the MPG has improved. Still, I'm experiencing those acceleration issues.

The previous owner parked the car on a donut tire for a while, and it was just collecting dust.
What do you recommend I do from here? I’ve never worked on a hybrid vehicle before and have mainly just worked on mopeds and scooters, so my mechanical knowledge is quite limited.

That being said, could you recommend troubleshooting steps from least difficult to most difficult? I appreciate any tips and recommendations!

Thank you!