Hello,
I've played M2TW online twice and Kingdoms only once. The M2TW games were 1vs1, the two (two games, one evening) Kingdom (Retrofit) games were two 2vs2 (hosted 4vs4, it just didn't fill).
There are some claims about the performance, especially the required connection. 1mbs or 10mbs is a big difference. It's safe to say it's demanding? A team competition is nicer than 1vs1. That will put more stress on the hardware and connections, whether noticed or not. I think it's valid to go with local tourneys in that case to optimise fun.
What you say about people leaving is a reason to focus on local too. People can always choose to look beyond the border, even cells can decide to stick together again when conditions improve.
It's good to make the best use of what you have.
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