I'm planning on flashing LineageOS on my phone to debloat and to degoogle, and additionally to increase overall privacy but apparently from what I've heard here that it's not private enough or even at all?

I know about it being less secure because of the opened bootloader and the higher chances of you rooting to achieve what you want with a degoogled phone, but beyond that (especially privacy-wise) I don't know anything.

I've seen a video on how to degoogle it further, but surely it isn't all I need to do.

I need some education.

Unfortunately my phone is so obscure that it isn't supported by literally anything, but fortunately there's an unofficial port of LineageOS I found on Telegram, and that's the one I'll be using. So if you're thinking of suggesting another custom ROM, you're out of luck. Also you can't make me buy a Pixel - that thing ain't supported in my country (5G and others) and it's hella expensive as well.