Well if they can deceive certificate authorities that implement the ACME protocol like LetsEncrypt, then they could get a certificate for your site with the HTTP-01 challenge, see the paper Using BGP to Acquire Bogus TLS Certificates (2017) [1]. That paper suggested a mitigation they call Multiple Vantage Point Verification, which has already been implemented [2].
[1]: https://petsymposium.org/2017/papers/hotpets/bgp-bogus-tls.p...
[2]: https://community.letsencrypt.org/t/validating-challenges-fr...
They don't need ACME to do that, ACME is just an automation standard - the same rules apply for getting a certificate via ACME such as 3.2.2.4.19 "Agreed upon change to website - ACME" as for the manual process 3.2.2.4.18 "Agreed upon change to website v2". The ACME version is just designed for machines to automate easily (and as a result wildly more common in use today)
And Multi-perspective only helps against an attacker who is merely able to influence a local route, if they can ensure all your perspectives see the same thing the attacker wins.