The only comparable network to Tesla is EA and they hope to be about 3/4s the size of Tesla's network by early 2022.
In my opinion, 99% of everyone worries far too much about the road trip use case and completely overlooks that most people will do almost all of their charging at home.
The big exception is Electrify America, which has about 600 sites now. Its good enough for many right now, though it isn't as deep or reliable as the Tesla Supercharger network.
Tesla supercharger coverage is pretty good with just over 1000 sites. EA coverage is actually pretty good too with just 600 sites. The # of sites needed for L3 in the short term isn't really that high. The number of plugs is important. I think EA averages 6 plugs per site, and Tesla is a little over 8 per site, with most new sites being 8 stall setups.
I would like to see Tesla transition to CCS in the US but that's going to be a hard sell without legislation.
*exception being CHAdeMO, but those are becoming so rare now as to be not worth consideration.
The biggest difference is that there are more DC fast charging locations for non-Tesla EVs but they tend to have fewer chargers per location. Superchargers are less common but there are more chargers at each location.
Both chargers have less than stellar reliability, but I'd give Tesla the overall edge there. But the third-party networks are growing much faster overall, and the quality of their infrastructure is improving dramatically as well. At some point in the next couple years I expect Tesla will need to find a way to allow their cars to take advantage of these other fast-charging options, to stay competitive.