It'll be a monument.
Every other monument we have yet made lies within the solar system. The voyager probes are humanity's first physical journey beyond our home. It's human curiousity reaching out into the cosmos for the first time. As cosmic infants walking outdoors for the first time. Even if we eventually pass them some day, they were still the first.
And even more, there are plaques on them waiting for that 1 in a trillion chance to be found by a distant alien race. Long after humanity goes extinct those plaques will endure. Even if we can see the beginning of the universe with telescopes, those telescopes are near to our planet.
The voyager probes could potentially exist in the future as the only thing outside of our solar system to prove we ever even existed....hell depending on how and when we go out, they might be the only things anywhere
edit: I forgot about pioneer. pioneer 10 and 11 were launched first but voyager 1 and 2 left the solar system first. Also there is new horizons. 5 probes total.
Pioneer probes had plaques and voyager 1 and 2 have gold records that can be played if assembled correctly by aliens. Lol https://en.m.wikipedia.org/wiki/Interstellar_probe#:~:text=As%20of%202024%2C%20there%20are,three%20are%20on%20interstellar%20trajectories.
Yo I thought the voyager probes were the only probes that have ever left the solar system that's crazy
Now I'm gonna have to look up YouTube videos about all of pioneer missions.
Edit; I'm conflating these 2 probes with the voyager probes. The plaques in thinking of were on Pioneer probes. I think my brain has been mixing facts from pioneer and voyager for a while
Edit 2: voyager 1 and 2 are the only ones that have actually made it past the boundary. https://en.m.wikipedia.org/wiki/Interstellar_probe#:~:text=As%20of%202024%2C%20there%20are,three%20are%20on%20interstellar%20trajectories.