I hibernated my Inspiron and now it does not power back on

Disconnect both the primary and CMOS batteries, and hold the power button for 1 minute, and try again but turn the laptop on before reinstalling either battery; that sometimes helps and if the CMOS battery is dead then it's easy to tell that way. For some annoying reason, some Dell laptops from the 8th gen era inherited the E7440's CMOS battery voltage sensitivity nightmares. However, disconnecting and reconnecting it (as well as the primary battery, to make sure the system is drained, and the CMOS RAM will be defaulted) often quickly fixes the problem. I've even seen 7490's get sold "as-is" due to this issue - which is why I have a $150 7490 with the 8350U/FHD LG IPS LCD :-). No mine isn't the top spec edition (that's a 4K IPS Touch/i7-8650U/32GB RAM/biggest SSD you can squeeze in it type, these are available BUT are rare) but I came from a bum with a dirty past (active lease where the machine was suspect, with liquid damage. I took what I could at that time.

Yes, I have seen 768p BOE TN ones (I have one as a throwaway with the 8250U) machines, but most of them either have the LG IPS LCD, or the BOE IPS LCD (both are good, but LG is WAY better).

The permanent fix to this problem is a new CMOS battery, especially if it tests at 2.5V or lower (use a cheap multimeter, even a cheapo one from Walmart will work to check these batteries as they're low voltage). Follow this guide to open up the laptop to get to the CMOS battery. On yours if it's dead, you can run out to any store that sells the bare battery and quickly purchase a new one, since there are no leads on this laptop. Even then, your battery is so cheap it wouldn't hurt to just change it to ensure its mitigated. I consider it a consumable item like the primary battery once the computers known to have this problem enter the hands of DIYers at Walmart special prices, especially once the R2 facilities begin selling them off without SSDs.