Just after writing
this post in the other V&R thread, I thought to go to bed... and saw a brown envelope sticking in the mailbox (a "slit in the door" in most of the Netherlands).
It wasn't there at around 19:00, so it must have been delivered very late indeed.
It's the new SIM-card.
This time, I put it into the phone, and it was immediately recognized, with "No Service" as expected. Activated it, then turned on 4G (which you can turn off and on with this carrier, for some reason... maybe useful if you're in an area where 4G doesn't have good reception yet, even though you can choose 3G as a preference on the phone itself), and everything worked in about 15 minutes.
The phone doesn't give any strange notices, 4G/Internet works, and I was able to receive Whatsapp's verification SMS, so I assume I'll be able to send SMS's and make calls. I'll see tomorrow.
Now I'm going to look for a good back cover. Even though this phone is not made from glass like the Nexus 4 was, it is WAY too thin and slippery for my liking.
It's close to the perfect phone for me. If it had been 4,5 inches, like the original Moto G and have the volume and power buttons located where they were on the Nexus 4 (exactly right for someone holding the phone in their left hand when calling), it would have been perfect.
Because of the fact that it has a replaceable battery and the 4G -> 5G transition in the Netherlands only beginning in 2021 (estimated), I fully expect to use this phone for at least 4 years, maybe longer, assuming it can handle future versions of the (very few) applications I use.