If you want to get up to speed, I'd of course recommend Arch but I got two other worthy ones:

Adeptus Ridiculous is an unofficial W40k podcast where they have Youtuber Bricky explain and go through the history of each group and fraction in 40k to a newbie so a good starting point if you're new.

Luetin09 does great breakdowns of W40k too

Those two I know not from 40k but when they were Warframe and Battlefield YouTubers respectively. It's like when you get burnt-out thanks to game companies, you enter the grim dark universe lol.

If you want to get up to speed, I'd of course recommend Arch but I got two other worthy ones:

Adeptus Ridiculous is an unofficial W40k podcast where they have Youtuber Bricky explain and go through the history of each group and fraction in 40k to a newbie so a good starting point if you're new.

Luetin09 does great breakdowns of W40k two

Those two I know not from 40k but when they were Warframe and Battlefield YouTubers respectively. It's like when you get burnt-out thanks to game companies, you enter the grim dark universe lol.