There seems to be a bit of difference in what people mean by 'microservices' - some orgs will have a few REST collections per 'service' so you might end up with 'users', 'products', 'transactions' as your three services, and it being totally unimaginable that you'd ever break 1000.
I'd argue that's still a Service-Oriented Architecture (SOA), but I'm sure it's not anywhere near as 'micro' as what Monzo counts over a thousand of.
Thanks for replying, that does clear things up. My experience didn't really embrace RPC, so used gRPC for one small bit (< all of the service that contained it as I recall) but most was JSON HTTP APIs - the service boundaries pretty much just being team boundaries, though some (incl. mine) had a few services to the team.