I’m very sorry. It looks like you did a bit of work yourself. If your battery isn’t 100% dead then there’s more work to be done. Typically a system will boot and run, albeit slowly without a battery at all. Unfortunately the blink codes are probably coming from a “sub processor”, aka the charging system. That usually happens when that’s the only system that is working. Taking out the battery and trying to get anything will tell us all more.
Fairly recent phone? Uh they use liquid focus tech or piezo. A field of electricity changes a tiny amount of liquid/solid to achieve focus. How is the glass removed? Usually a heat gun, which is fine anywhere EXCEPT the camera. The process either warped the mechanical lens assembly or evaporated the liquid. Either way an overheated camera=seized focus. Thankfully they’re tiny little click in modules, and fairly cheap. I’m amazed a repair shop didn’t know basics of camera operation.
Can you rotate the engine at all? Take out the sparkplug and see if you can rotate the flywheel at all. If you can it’s probably electrical harness, etc. If you can’t, it’s either seized or broken rod.
Broken usb port problems are extremely common. Even sometimes caused by a slightly too large usb cord connector, etc. It’s usually fairly straightforward to fix, unless it’s totally loose and it tore up the board. In many cases it’s still fixable depending on where it tore. I do laptops and tablets & often have to use superglue and jumper wires, so far have had about 75% success.
If when shining a flashlight into the screen you still see things. It’s probably a backlight issue. LED’s often last a really long time. LED drivers and power supplies, not so much. The top three failure inducers are temperature, power surges, and cheap parts. Also if the power light is blinking or odd colors the TV itself is trying to diagnose the problem for you!
Try “Aigning the print cartridges” from the built in menu. If that doesn’t work it’s possible the carriage height is somehow messed up. Happened to me when I tried to print on too thick paper. It worked great on the thick paper, but afterword regular paper had that “spraypainted” look to it.
Many newer laptops with mini chargers absolutely need the battery to provide extra power when the cpu clocks up. Also most units now use both an age & genuine check. If the battery wasn’t “fresh”, you’ll have all the problems you described. It’s not the actual battery cells that are bad, probably bad data on the “on battery computer”. Batteries aren’t dumb anymore, they have their own data and safety processor. I used to rebuild batteries & reprogram them as certain computers could never recognize a “replacement”. I know there are some battery utilities out there to update the date & recalibrate the unit. Probably not an option, but there may be one out there.
Either the battery is dying, or the on battery computer has bad data. Sometimes in BIOS there is a battery recalibrate function. There “might” be a utility to reset the battery data as well. But that’s only if the battery data is wrong.