Sim2Fly isn't the easiest to keep active if you don't have a Thai bank account. You have to go through third party top up services and the physical sims are usually registered to someone else if you get it outside Thailand via reseller. esim2fly is run by MobileTopup.com. Not sure if you need to provide a passport number to register it to you or if they register it to another person. The top up services can be finicky about which credit card verifications they'll accept Prepaid SIM discussion (consolidated)

I've used Sim2fly in Japan and would consider a service with a more direct payment system but probably not Airalo. Airalo uses China Unicom roaming in Asia including Japan. I went with 3HK esim last time https://www.three.com.hk/eSIMMall/ch...x.jsp?lang=chi 10 days for $138 HKD or ~ $17.71 USD. Fair use is 500MB high speed per day and after that it gets throttled.
Translate from Japanese for more info on how to keep 3HK topped up https://esimdb.com/ja/blog/3hk-esim-recharge-process/