You can literally set up your own OpenStreetMap instance in ten minutes. It's a simple 'docker run'-command. Sure, indexing will take a bit but even that can't take that long given their resources. That's just ridiculously greedy.
A while ago I very briefly tried Headway out of curiosity. This is the easiest Docker based option for the "full stack". It didn't work out of the box. Things went wrong. Which is no surprise, there's a ton of moving parts. And maybe it's not a big deal to work around but I highly doubt that it's 10 minutes of work to get everything working reliably.
I used OSMRouter maybe 7 or 8 years ago to process a couple billion routes and it was about as simple as GP described. Just need Docker and an index file. the US one was massive so I kept needing a bigger VM just to load it, but once I did I was able to make HTTP calls over the network to get what I needed. Took a few days to get a working setup but only a few hours to rip through billions of requests, and I was making them synchronously with R; could have been much faster if I was smarter then.
