I always use Carbon Copy Cloner for swapping/cloning drives because it is '''''so much faster''''' than Time Machine. Absolutely everything is mirrored to the external drive and you can test the external drive before pulling your machine apart.
You can get a 30-day trial of CCC at https://bombich.com.
''(I have no affiliation with Bombich Software and receive no benefit from your use of CCC.)''