Got a android recently and wanted to replace the default os with a new one, I've seen mentions of others (lineage OS, Graphite OS) but wanted to know what are some good ones and why.
Before getting your hopes up: Check if your specific phone model is supported by any of them. On lots of phones you can't change the software and you're stuck with the manufacurer's version.
Good idea. I think GrapheneOS won't work with that as they're focused on the Google Pixel devices. But you could have a look at the LineageOS compatibility list. Just the manufacturer is a bit unspecific. But you can look up the exact model in that list.
I can't really comment on all of the other Android variants. There are so much of them and I'm not up to date anymore.