@tkerby please have a detailed description about all the operations you have done to the deivce since you got it, and if possible, show the logs of the recovery tools you have tried. there are a few...

@Franz99 May I ask your location(country), pls？

@Franz99 have you removed the battery after the update? if not, you can have a try and resinstall it, then see what happens. can you name which led indicator blink? and under what circumstances？

Send all the logs here,pls

Can you try another sim card from a different isp? Is the pocket wifi allowed to use the sim card for phone ? if so, you can try it, The wifi may be interfered with other 2.4G devices, so the wired...

@DOSSIP47 What's the exact version of your M7350 ? What's your environment like when using the device? Have you try the same sim card on your phone and see its speed and stability? if not, you can...