Could you give me am example lift? I have been doing 5x5 really heavy. Would I switch to like 3x10 heavy then from that a high intensity low weight workout on the same muscle group?
no. if you wanna keep your strength, you need to lift heavy. it provides the proper stimulus to keep the strength. id recomend staying on 5x5 (because its an awsome routine) and add in cardio on a couple off days. not overkill on cardio either, maybe 2xweek and youre golden
the primary factor here is your diet. you can cut without any cardio at all if you know how to manipulate your diet
idk where you stand now, but if you can, then go for the hiit training. if not, light cardio is fine too. the goal is to create a deficit in calory expenditure. you can do that by 2 ways: exercise, or eating less calories
you can also go swimming. thats arguably the best form of cardio because it wont stress your body like running does. that means it wont cripple your squats on the 5x5 routine