Board Game Arena

Hi, apologies if this has been asked before. I tried searching the forum first, but I struggled to do any meaningful search as ELO and Arena are flagged as common terms and excluded. Mods if there's a good thread to read please feel free to just link it and close this

I just played a couple of games of Cartographers in Arena vs the same opponent. My Arena score is in the 1800s and their's in the 1500s. Also my ELO is in the 500s, their's is in the 200s.

I lost the first game, and the change was +/- 35 points.
I won the second game, and the change was +/- 7 points.

I appreciate that I'd lose more than I gain due to ranking/ELO differential. But based on the above I'd have to beat that opponent 5 times just to recover my 1 loss, and I'd have to beat them 6-1 just to get a small increase. That seems crazy?

Yep, for an elo (or EAS in this case) difference of 300, the expected win rate is around 85% https://wismuth.com/elo/calculator.html ... ula=normal
This means you're expected to win 85 games and lose 15, or win 17 and lose 3, or win 5.67 and lose 1.
If you win more than that, the difference will increase. If you lose more than that, the difference will decrease.
If you play against higher-rated opponents, the expected win rate will obviously decrease and you won't need to win as often (because it's supposed to be harder).