accessing data on a broken macbook pro
If this were the 2018 model, you could &quot;trash&quot; it and not worry (too much at least)  about your data (there's actually some vulnerabilities, but that's for another day and another question).  The T2 chip would make it virtually impossible for anyone to access it.  If you encrypted your drive, then you're essentially protected from bad actors trying to steal your data.
Booting in Target Disk Mode
If you boot your computer from an &quot;off&quot; state, just hold down T for about 30 seconds - that should be enough time to allow your Mac to enter TDM.  Normally, you'd see a USB icon on the screen, but now you're forced to guess; 30 seconds should be sufficient.
Once the target is started, boot your &quot;good&quot; Mac using the &quot;bad&quot; one as the startup disk.  You should then be able to get in and wipe out your data.
Genius Bar
This is something the folks at Apple can assist with. Your particular model had something called a &quot;Lifeboat&quot; circuit integrated with the SSD.  You could literally have a dead MacBook logic board, but with a Data Migration Tool kit you could access the SSD to recover your data.  It's an expensive tool, so it's not DIY, but Apple and 3rd party repair shops would have this so they could offer the service.
Does it have value?
As unlikely as it might seem, your machine still has value.  Apple makes it impossible to obtain certain chips like the SMC.  It's made by Texas Instruments (TI), under an exclusivity contract; nobody can buy it in the open market.  So, if an SMC dies, the board repair companies cannot buy the component to fix.  So, they use donor boards for this type of repair.
Normally, donor boards were sold as complete units.  Now, they are literally being &quot;carved up&quot; like a Thanksgiving turkey - a wing here, a thigh there, etc.  (Seriously, not kidding).  If you want to sell off your board, remove the logic board and put a drill through the solid state drive.  That will ensure that your data is secure.  They wouldn't be able to use that component anyway due to the security, but it doesn't hurt to take it one step further.  For a &quot;map&quot; of where the SSD is, just take a look at the iFixit Teardown for your model.
Get a second opinion
Before you trash it, have someone who specializes in board repair take a look at it.  Rossman Repair in NYC does this and is considered one of the best (not affiliated, just a happy customer).  Without putting hands on, I obviously can't give you a budgetary quote, but you could conceivably get this repaired for less than $500 USD (guessing here).  It doesn't hurt to get a second opinion.  The plus side here is if it's not worth repairing, they can recover your data for you.