Free geoip database is very so-so, at least for residential addresses. For example, my ISP is of Romanian ownership (Digi), and although I'm Spanish, located in Spain, and using a Spanish contract (not roaming at all) for years (not a recently arrived ISP), I'm still very frequently shown Romanian versions of ecommerce sites I visit from my phone or home connection.

But I wonder: shouldn't at least intermediate router/exchanges locations be better pinpointed through their who is information? Isn't that database updated?

I wonder how reliable is JA4L once you start adding hops in the middle of the trace, I guess it takes in account the timing of the intermediate points.

A little time ago (1 month? 2? I'm so bad with dates) somebody showed their IP location service that was built using a similar technique, but measuring from multiple different locations, and I think they had a free version of the database. I'll try to find it later.