Also PSA for newbies: Raspberry Pi Model 3B+ with a (fast) USB 3.0 HDD takes literal weeks to sync and verify the whole blockchain. Either have a real desktop (maybe also laptop with enough umph) Linux PC with which you can do the initial sync, then plug the drive into the Pi. Or use an SSD. Just wanting to prevent tons of headache 
I cannot stress this enough, get away from the RPi3 in general at this point to do bitcoin stuff.
It will work, but the RPi4 is just a better unit for not much more money.
Since they say a picture is worth 1000 words and I am too lazy to type, the following image from https://magpi.raspberrypi.org/articles/raspberry-pi-4-vs-raspberry-pi-3b-plus
puts in out there perfectly:
All that extra processing power for $20.00 more.
I know that due to the current shortages prices are all over the place, but you can still here in the US get a 4 with 4GB for $50 delivered give or take a few dollars.
A year / 18 months ago it was a different story. Now, just get the 4 IMO.
-Dave