First off? Do you have a current Pixel phone?

Because GrapheneOS is only available for Pixels, and current ones at that. I’m still on a Pixel 4a, and GrapheneOS considers my phone end-of-life and support for it will eventually stop.

Secondly, since you’re less tech savvy, you’ll probably want to use the official installation via WebUSB but as a point of warning, Firefox purposefully chooses not to use WebUSB or WebSerial because of security risks.

Google built WebUSB and WebSerial because Chromebooks are a useless fucking joke of a computer without them, since it doesn’t have a real OS, and just a glorified web browser. This is fuckstupid, pathetic, and absolutely a security risk.

That being said, the WebUSB install is definitely going to be the “easier” path for you, but you’ll be forced to use Chrome to do it.

Are there any known issues with it like slowness or not being able to use the camera, etc?

No idea, I always went LineageOS because it supports more devices, has better support for Google services, and isn’t quite as obsessive about privacy. Unlike GrapheneOS, updates for devices will come as long as maintainers are able to make new versions of Android run on older hardware. With LineageOS, I’m looking at likely years of security updates for my Pixel 4a.