S01-05 is on BTN.

S02E02 is available on BTN, with a bounty on S01.

A comment on the bounty links here: https://www.reddit.com/r/NHKWorldFans/s/62WWjARH08

Does anybody have any suspicion about what service it is?

I have not used it for streaming, but you’re right. I purposely do not proxy my media traffic for this reason, utilizing their other solutions.

Everything I see online says it’s free.

I’ve also used it recently and did not pay for it.

You can use Cloudflare Tunnel as well.