2010 Gen 3 Bad Battery - need advice

First time poster here and could really use some help from the experienced Prius Chat community.

I have a 2010 Prius with 134k miles that I purchased 2 years ago (I live in Orlando). I have loved the car and it's worked great until last week. Was out of town for 10 days, came back and got the Check Hybrid Engine warning first thing. Got a OBDLink LX OBD2 scanner, checked the Hybrid Assistant and Dr. Prius apps and both showed the P0B3D error code (Hybrid Battery voltage sensor A circuit low).

Took to the Toyota dealership today. Didn't know if I would make it there as the car was acting weird and when I shut it off at the dealership the front of the car shook and made a bad noise. After inspecting, they told me one of the cells is completely dead in the first block (P3011 error code). They checked 12v battery, for wiring issues, corrosion, ECU issues and said none of those were the problem and that the Hybrid battery needs to be replaced. Initial quote was for $3695 ($2800 for battery, $895 for labor). I searched prius chat for comparison costs and compared costs at every Toyota dealer within 100 miles. Best deal was $3028 for the battery and labor. Asked my dealer if they would match that deal and they said yes. Told him I needed to sleep on it because it's hard to stomach paying $3000 on a car that I paid $6000 for 2 years ago.

I need advice. Would you pay $3000 to replace the battery and start fresh so to speak, try some DIY options to replace the 1st Module (I am a novice but willing to learn...just a really busy time in my life right now), find someone local (feel free to send recommendations) that will can replace the 1st module and rebalance the battery, or sell the car and look for another car (how much could I get for a 2010 Prius with 133k miles that is in good condition besides the bad battery?)? I was planning on keeping this car for at least 5 years with the hopes of keeping it for 10 years in case that's helpful.

Only other consideration is that the vehicle condition report from my last service visit in August (at a different Toyota dealer) showed that a timing cover reseal needs attention soon due to a timing cover leak. He said that I should be good for at least one or two more services but that it might need to be done at some point after that. Quote was for $4300 with taxes (3800 in labor, 200 in parts, rest in tax/misc). I don't know how legit that need was and if it will truly need to be done at some point in the next year or two or now...but if it does I feel like it definitely doesn't make sense to sink $7300 into the Prius that I paid $6000 for 2 years ago.

Your advice and help is greatly appreciated!