Won 7 out of 11 ranked and finished in the same place that I started...

Between yesterday and today I've played 11 ranked matches. I won the first 5, promoting from Plat 2 70LP to Plat 1 0LP. From there, I won 2 and lost 4 (W, L, W, L, L, L) and demoted back to plat 2 75LP. I wasn't at 0LP until the 11th game, so it's a bo3 to promote and a bo1 to demote?

If demoting means losing 25 LP, why don't we get any kind of overlapping LP that would carry over into the next division after entering promos from 90+ LP or from winning promos in general? At least then there would be a tangible safety net at 0LP, so that we're not wondering why sometimes it takes 1 loss at 0LP to demote and sometimes it takes anywhere from 2 to 4 losses.

This system currently is too punishing and grindy. Even in elo where I gain more LP than I lose, I still need to win over 2/3 or 66% of my games to climb over divisions and tiers, where I can demote in half the time it took to get there. If this isn't going to change, then I need someone to explain to me why losing is inherently weighed more than winning.