I remember some really good public sites, but the quality cycled up and down and the Pokemon devs fought back a bit. I used some tool that basically was what OP

I remember some really good public sites, but the quality cycled up and down and the Pokemon devs fought back a bit. I used some tool that basically was what OP described, but let me easily self-host a server. At the time I think there was some hack where the server component could fake location, so you'd just send it off to walk a geofenced area and could browse on mobile remotely while playing the game. Ran it off my laptop, then a DO droplet. Good times.