FYI Social.coop just patched Mastodon using a pretty hacky approach (docker-compose.yaml-based source code patching) to avoid having to move to a fork of Mastodon and/or build our own images; this, it seems, is what many instances around the Fediverse have had to do due to the #Mastodon project not prioritizing making character limit customization possible and declining PRs that tried to advance in this direction.
We got away with customizing this without forking (and paying the associated cost, and diverging from Mastodon mainline which we try to support...) but not all instances can afford to do this. I hope the project can become more open minded about supporting customization, given that so many instances would like to use the #Fediverse in ways that you might have not completely foreseen in advance when you decided on relatively arbitrary limits many years ago.
Thank you for your consideration, for what you do for the commons, and have a great day!