You're still missing many other significant factors besides distance. There are many conditions that affect latency, but on the minimum theoretical value possible, it's mostly dominated by the slowest path technology's single channel bandwidth. The other factors that reduce performance include:

- Network conditions

- High port/traffic oversubscription ratio

- QoS/packet service classification, i.e., discriminatory tweaks that stop, slow, or speed up certain kinds of traffic contrary to the principles of net neutrality

- Packet forwarding rate compared to physical link speed

- Network gear, client, and server tuning and (mis)configuration

- Signal booster/repeater latency

- And too many more to enumerate exhaustively

As such, point-to-point local- and internet-spanning configuration troubleshooting and optimization is best decided empirically through repeated experimentation, sometimes assisted by netadmin tools when there is access to intermediary infrastructure.

I wasn't enumerating all sources of latency. I wrote largely, as after some amount of distance all the other factors are not really relevant in a normally functioning network (one without extreme congestion).