How did you determine that Bunny lacks IPv6?

The CDN certainly has it: https://bunny.net/blog/ipv6-returns-to-bunnycdn/

Depending on where I query from, OP's blog does have it as well:

    # host jola.dev
    jola.dev has address 37.19.207.38
    jola.dev has IPv6 address 2400:52e0:1a04::1310:1

Seems @zorked is correct about some POPs simply lacking IPv6. I simply happened to hit one of those. Quite disappointing but I guess Bunny is on the cheap side and doesn't actually own or manage their network like big CDNs do.