If you have no preferred pronouns, just say (none) or something
This will help make people feel more comfortable in this comm and has a side effect of showing you support trans people when making comments in other communities. It will also make reactionaries seethe and make it easier for mods to purge them, and make trans people feel safer all over the fediverse.
the point is to affirm trans identities, by putting those in you are showing you support and affirm trans identities.
showing pronouns is not a requirement to be trans, but it is a requirement going forward for this community in order to remove reactionaries. people will be asked to change their IDs. if they cant due to their instance, thats fine.
the rule explicitly states cis people should show pronouns as well. knowing if someone is trans online (and seeing many others) does have practical benefits in attracting more trans people to a space, though. but this isnt outing yourself as trans, just showing pronouns.
it certainly does work for all, it takes a couple of seconds