A vote for a third party under FPTP is mathematically a vote against the party closest to your values. If you live in the US, that means you vote(d) against the Democratic Party and for the Republican Party.
I too long for a third party, but 2024 is not the time.
Unfortunately, most people won't understand this and still vote for third party even when third party will almost certainly never win, in the context of present day Murican politics.