Some data points/observations/rant on a couple of prepaid data only tourist oriented esims.
I have 2 phones to setup for in Japan. I got one on the Navitime AU/KDDI 5G on one phone, and world-esim.com that is connected to Rakuten's 5g network, but APN is a three.com.hk/hutchhk. I was hoping that it would not have an APN in chicom controlled areas (Hong Konger here), but I guess world-esim is probably the 3rd or later layer of the onion. My research was incomplete, other than seeing that it was a company located in Hawaii, and cannot get the APN info until the you bought the thang email. I rolled the dice and lost.

Did the meter.net ping test on the Navitime phone. Japan server was about 30ms, to the US Server was about 160ms, so as expected.
Got 135.8 Mbit/s down and 17.53 up on the JP servers for the speed test.
Will update with the world-esim numbers when I get them.

Probably should've just went for ubigi or one of the BIC ones that use docomo 4g for the 2nd one as I wanted docomo. There was one small store on 2F to the right of the arrivals exit at Haneda T3 that offered 5g docomo unlimited for 3300 yen, I forgot the duration, probably 1 week at that price. In the end I should've got that, but passed on it. I looked at BIC and Family Mart and Lawson for a 5g capable prepaid traveler esim, and did not come across any. I wanted the 2nd phone to have different network than my Navitime AU/KDDI. It seems if you want a JP sold online 5g prepaid, Navitime maybe the only option, not 100% sure but it sure seems that way. Seems like no options for in person purchase other than at HND. After seeing how each performs on this trip, my goto for Japan may well end up being Navitime-AU.

AU 5g seems to run down my battery quicker, or it could simply be that I'm using the phone more here than back home, not sure which is the "right" answer.