Which stable coin do you prefer? And which chain to store it?

[BayekSmith]

Hello,

I'm going to exchange all the BTC into stable coin and wait for a dip to buy back. I'm going to use USDT since it's the most popular in my country. But I see some people prefer USDC or DAI. So, what's your choice if you were me?
And I also wonder which chain should I choose to store large amount of stable coin? BSC, Tron, Polygon... which is the safest and cost effective when moving?

Thanks!