Can someone please point me in the right direction or suggest a tool they like. I'm running Ubuntu 20.04 on my machines. TIA.
I've done a lot of work with WWVB over the past 19 years. I designed a receiver that decodes the legacy time code and also serves as a 10 MHz frequency standard.
My receiver uses a PIC16F88 Microcontroller to decode and display the UTC date and time. It also produces an RS-232 output that can set my Slackware Linux workstation to within 1 millisecond of NTP:

An article describing my receiver appeared in the November/December 2015 issue of QEX magazine:
http://www.arrl.org/files/file/QEX_Next_Issue/2015/Nov-Dec_2015/Magliacane.pdfWWVB transmits its time code at a rate of 1 bit per second, and it takes one minute to receive an entire frame of data. As such, even a PIC running at 4 MHz is
overkill for this sort of thing. Imagine a multi-core 3 GHz Linux box...
So, my approach was to handle the RF processing, filtering, and synchronous demodulation in hardware. Then have the PIC decode the time, run a clock/calendar in its firmware, and use an RS-232 connection between the PIC and the PC to set my PC's clock.
Otherwise, the receiver has its own LCD display to show the current date, time, and UT1 offset as well. No external computer is needed.
Food for thought... I know that's not the approach you were interested in, but I am not aware of any "purely software" approaches to WWVB reception. I remember hearing about one for DCF77 on 77.5 kHz in Germany, but I believe it is a Windoze program.
73 de John, KD2BD