can I use my mac m1 30 watt adapter to charge iphone 13

You could use a 100 Watt adapter if you wanted and it would not harm your iPhone in any way.

if the connector fits you can

no as stated, an iphone will never draw any more power than 18watt and anything else will just be unstabbed charging captivity, the phone and battery for that matter has no idea it's not just charging with a 18watt (they only really sell 20watt but anyway) ac charger.