Is there any hope of me getting the blooming dreams dress for free? (Details within)

I didn't read up on the gacha system before spending a lot of diamonds on the permanent banner...

I've done 148 pulls so far on the blooming fantasy banner. I've redeemed all codes etc, got the battle pass... No stellarites left. I really don't want to spend any more money but do you think I can grind enough in 5 hours to get 50 pulls?

I've extensively explored already so not sure how many chests etc I have to do.... Ahhh! I wish I'd read up on it first :(

Thanks!