This isn’t how trademarks work, unfortunately. A trademark is something that only your business gets to use. Your unique use of the trademark means anything using it comes from you.

You can grant others the ability to use your trademark. Without that approval process that has to go through you, anyone could use it, though. If you don’t attempt to enforce your trademark, you could lose the mark depending on the extent of the infringement. Different folks will tell you different things there.

Trademark law is actually pretty useful. I say this as someone who is generally quite anti-IP. If you really want to not involve trademarks, just don't enforce it, and you'll lose any trademarks you've got afaik (IANAL, this is not legal advice etc).

What exactly is your worry here? Imagine you've started your project with distinct branding of Foo, and someone comes in and does something you really don't like. Maybe it's adding a gaping security hole in the name of adding a "feature". Maybe it's saying "this project is for Nazis only". The traditional response in open source is to say "fine, you do whatever you want, but create your own fork in a way that won't confuse people". IMO that's fair and square. What happens though when your project Foo gets a bunch of complaints because someone created a "foo" package that secretly replaces all of your keyboard input with swastikas? Trademark lets you say "don't name your package foo, because it's confusing to us non-Nazis".

You might look at the licensing terms for the "Linux" trademark, for one well-known example. There are both formal sublicense terms that businesses and projects can sign up for if they use "Linux" as part of their own trademark, and also stated terms for the use of the trademark without a formal sublicense.

https://www.linuxfoundation.org/legal/trademark-usage
https://www.linuxfoundation.org/legal/the-linux-mark

The FAQ section of the latter page may be especially informative as it also covers some topics like "what is a trademark?"

In most cases you don't want one. It can make forks confusing and lend malicious actors more credibility than they deserve.

Copyright controls the code. Trademarks are the recognisable names/icons that identify a project.

Trademarks are not an issue per se. It is IP. In a world without IP Trademarks would be an issue of fraud, not "Intellectual Property" - and then only for the customer.

Others gave good reasons against, but I'd like to find a way through. Without knowing much about your project.

What if you classify it as art, whatever it is? Others are free to use, change and copy it, as long as they themselves allow the same with theirs.

Thank you everybody for your feedback, this has been helpful.