yes, yes they are.
Start with Yakuza 0, given it's a modern prequel that actually sets out the whole lore/ongoing storyline and tone. If you like the beat-em-up gameplay and actually want to see the story the whole way through, move on to Kiwami 1 and 2, but note that they're remakes of PS2 games if they seem light on or janky. Then feel free to play the HD collection if you really want to slog it out through the whole series - I hear 3 is especially rough, never played it myself.
Otherwise, you can pretty much safely move from 0 to Like a Dragon / 7 given the hard reboot in terms of protagonist and genre/playstyle (becomes turn-based combat with what I think is a pretty funny storyline justification). 0 gives you the backstory, lore and location knowledge that you really appreciate when starting from the Like a Dragon 'chapter'.
Also feel free to play spinoffs whenever/any time after 0. Judgment is like a full story spinoff but same locations, Ishin is "what if but samurai" so character knowledge improves it, Gaiden kinda spoils 7 so is best played between Like a Dragon and Infinite Wealth.
also, Nugget best boy and Omlette best girl