Payment methods are usually banks, so yes kyc. The only person to know you bought bitcoin is your seller. I don't have Strike, so I don't know much about it but I would assume the same. I.e. you pay the seller through strike and receive bitcoin to your wallet.

Robosats isn't too difficult once you get your head around it. You generate a token ( click a button) save it. From this token you are assigned an identity, a robot. You then browse the offers. You can even put a buy offer up and see if anyone takes it.

When buying, you have to put a small deposit down, via lightning. This is to deter time wasters. You give an invoice and wait. The seller will contact you, give you details how to pay. Once you've paid, the funds are sent to the invoice. If the seller does not reply or tries to not give you your sats, there is an adjudicator. It has never happened to me. I have requested to buy and the seller ran out of time. Then I received his deposit as compensation. You always get your deposit back.