That write-up makes it seem straightforward, but I am thinking something Pi-specific is probably a safer bet.

Unless you put too much current through wrong connections isn't it more likely they arrived dead? Too much effort to return for replacements?

Also is that deliberately plural - why multiple modules?

Yes, plural.
£2.35 each on AliExpress, and I usually buy two or more of things like that. Gives me the opportunity to use one in a prototype of whatever I'm making and a spare for a final finished unit (I make it sound like I'm manufacturing things!). Also in case I kill one and don't want to wait another 6 weeks for another.

If the components I'm messing with are much more than that price I won't buy multiple.

I think they might have been really old with dead onboard batteries. Tried to revive them with no luck.

Thanks for posting that. It made me investigate the modules I have.

Turns out one of them had some bad soldering across some IC legs. Fixed that and it has powered up and outputting NMEA strings. Need to see if it can get a fix.

It works (woot)

Woohoo! \o/

The other one is dead from what I can tell. But now I can attempt to make what I had in mind.