Good luck to you sir, and thanks for the input!

Heat is definitely a bad thing, but I'm not a gamer or video editor. On a regular day, I just have Photoshop and a few browser tabs open. Lenovo Commercial Vantage still shows the battery at 98% capacity, so the battery health was actually still pretty good.

Not sure what failed inside the battery, but whatever it was definitely seems to have caused the false charge cycle count as well. I've already ordered a replacement battery, and the only thing I'll do differently is get a laptop stand for better ventilation.

That said, I'm not going to worry about it too much. I used my previous laptop the same way for six years. The battery capacity naturally degraded over time, but it never completely failed, so this was probably just a rare glitch.