The rating swings are because you've not played many games of that particular type. Basically your grade is based on the results of your last few games, and the grades of your opponents.
So, if you've only played two games, then after your third game, the percentage you've won can go from 0% to 33%.. This produces dramatic changes in your grading until you've played enough games for the statistics to settle down.
The LiChess rating system is more sophisticated than just the win rate, but it takes time to settle down for the same reason.
LiChess has a page about rating systems,
lichess.org/page/rating-systems, which might help a bit.