Is simple: see what their app shows inside. If is showing only BTC symbol by default that means are the good ones. If is showing any other shitcoin fiat or worse shitcoins stablecoins or other crap, that mneans is a no go.

Strike is NOT a Bitcoin only company. Is just using LN to move value over borders. A kind of new Paypal, but with LN. That doesn't mean will push Bitcoin adoption but worse, will keep merchants using fiat.