The only thing that comes to mind is software or hardware. I would back up the phone on smart switch, then run factory data reset. I would test it first before actually restoring the data back on the device. If it seems to be fine, I would continue to restore the data EXCEPT for Apps. Test again and see if everything is working accordingly, then proceed with Apps to see if the issue persists. Check if there are any updates on the software. If it does persists after factory reset, it could be a chip related issue (assuming the device has not damages on it). If possible I would try to push for Warranty if that still applies and notate all the test you did. Hopefully this helps. Good Luck
If you have the sim card’s card the PUK Key is on the back along with the IMSI. If you don’t have the card anymore, contact your carrier and they should be able to tell you what the PUK Key is. I think, by default, the PUK Key is 1111. If you changed it yourself, or someone who accessed your phone, you will most likely need to replace the sim card.
I’m pretty certain there is a way to manually reset the pairing on your watch. Just like any other bluetooth device it should be capable of doing so. Re-pairing instructions I found online (1) Open Garmin Connect app; (2) Double tap on the face of the Vivosmart to activate the device; (3) Press and hold the face of the Vivosmart until the settings options appear; (4) Swipe through the settings until you see the Bluetooth symbol; (5) Press the Bluetooth symbol; (6) Press the right arrow once; (7) Touch Pair;
Blank screens after drops are common after a pretty hefty drop. Are you noticing anything vibrations when turning on the device? If so, it could mean that your LCD is just damaged and needs to be replaced. You could also attempt to see if there are any cracks behind the glass with good lighting. If you’re able to get another LCD that would be a way to determine it. The other test is if you have another A5 you can swap your board over to make sure it isn’t board damage related. This is just to knock out any other issues with the device. Good luck
Can you reseal it for waterproof protection, no. Typically, once a device is damaged or opened you lose the waterproof with the manufacturer seal. You can purchase a new adhesive that was made for that device, if available, and reseal the device yourself. Just keep in mind that it may not be completely waterproof, but the seal will help prevent liquid from coming it. Check the model of your device, I believe this should match your model. Adhesive seal
Are you testing the device with the back piece screwed on? If not, then that may just be the issue. The black plastic piece holds and pushes the board slightly, and that would make the board have contact with the vibe motor (vibe motor has 2 gold contacts that need to make contact with the board). Turn off the device, screw the top plate on and see if it works.
Have you looked into the water damage? There are basic steps you can do to see without opening the device. I have had some people who had water damage devices but when inspecting water barely goes into the device, which is something I find interesting with the newer samsungs. Basic Inspection. (1) Sim Tray- pop it open and remove the tray, look around for a White or Red marker (its a sticker inside the phone.) if you see Red, then water went inside the phone. If it’s white or white with purple marks, most likely minimal to no water went inside the phone. (2) Inspect the charging port - this one may be a bit more difficult if you don’t have a magnifying glass or sharp eyes. Get a light and inspect for Greenish debris/residue. If you see this, you can simply clean it with 99% alcohol, tooth brush, cloth, and a hair dryer on standby. Apple to the brush but not to the point where it’s dripping. just a small amount. Hold the device upright and brush it (literally like brushing teeth). Pat it dry and apply some...
Submit it to Apple Support and prove that you are the owner of the device or input the original Apple ID and its password that was associated with the device. There is no work around an iCloud Locked device!