Unfortunately this never can be solved fully because every printer behaves differently (e.g. i never have seen a printer so far printing out these valid PJL commands) and a printer needs to be detected previously that the existing mitigations are working.
See the following topic below for some more background information. As an alternative you can also exclude the known PJL / raw printing ports like 9100/tcp (please lookup your printer manual which ones the related printer is using) from your port list.