Soldato
I tend to buy it when I've finished it or done most of the levels as then it's free.I don't think I'm going to buy next season's battlepass, because you are literally forced to play every day to complete it and I'm not really that bothered about cosmetics.
At least with Battlefield 2042 you can complete the battlepass in a couple of weeks and then pick up the game whenever you want to play, rather than feeling forced, which makes it much more enjoyable for me.
"Easy" way to grind it is AFK in DMZ as you load it up, hide in a bush or shed, come back after 30 minutes and repeat. Battepass progress is 90% time in game and 30 minutes in DMZ is 30 minutes in game whereas 30 minutes in MP is 20-25 minutes in game and requires you to actually play.