Elasticsearch version conflicts?

Using: Cakephp 4.3, Elasticsearch 6.8

The ES plugin docs say that I should be using version >3, <3.4.0 of the plugin.
I’d like to use V3.3, which is the highest version in the range. Yet the composer file for 3.3 requires Elastica 7, which is for Elasticsearch 7.
So I tried V3.2.1, but that has a critical incompatibility with Cake 4.3: line 622 in Query.php: _execute() does not return ResultSetInterface (this was fixed in ES3.3) which throws an exception. I find this strange since that return spec has been present since Cake 4.0.0

For now I added the return type to the ES _execute(), but I’m not happy changing vendor code.

Is the documentation wrong and ES plugin 3.3 is the first version compatible with ES7? Or am I missing something?