Changing Pi-hole to deliberatly misinterpret files in hosts format won't give you anything.
As explained by rdwebdesign, Pi-hole already is capable of blocking domains including their subdomains, either by regex or - since Pi-hole FTL v5.22, Web v5.19 and Core v5.16.1 released in March 2023- by parsing lists in AdBlock Plus/Easy List ||domain.com^ syntax.
Block list maintainers are well aware of the different syntax of hosts and ABP formats, and they do compile their lists accordingly (as can be glanced from the default blocklist, which currently is in hosts format).
This makes 1) a very viable option, especially since ABP syntax blocklists were available long before Pi-hole temporarily dropped support for parsing them in 2019.