In reply to kevin stephens:
Your plan sounds sensible. Will you always have external HDD with you? i.e. do you need to import to SSD first.
My setup is similar, laptop has SSD with Lightroom and Catalog on it. Magnetic HDD is internal and has picture files on.
Folder structure on HDD (and in Lightroom) is Pictures->Year->Subject e.g. Pictures->2019->Devon holiday.
Import photos more or less on the day they were taken, direct to HDD. Quick scan through to delete dross, then add keywords for people and subject(s) e.g. climbing, flower, church, beach. Tag all locations in map module. Add stars to best photos, try and keep 4&5 star for the real stunners.
That deals with cataloguing, a bit of work on import, but pays back many times over when trying to retrieve pictures. Lots of backup strategies available, I find Syncback a good, free, program for keeping 2 drives synchronised.