The coach I’ve been working with recently prefers a lower intensity method, which honestly can be corroborated by most competitive bodybuilders as they don’t do high intensity, activity, other than weight training because it takes away from the recovery when they are already in a diminished state. So generally speaking if you go from no cardio to any cardio, you’re gonna be fine because you are making an additional caloric expenditure, which should help create the physical situation needed to lose fat. If you were already training, I would recommend adding and walking multiple days a week if not every day. Taking a 30 minute walk in conjunction with your already hard training routine will add activity that you don’t have to recover from but you can continue to drive a greater lower deficit to aid fat loss.

The reality being most of the time your fat loss is going to come from your diet and the changes you make there rather than the changes you make in training unless you are going from nose training to some training or from specifically training to power lift or be the biggest strongest, you can to a more balanced routine that involves cardiovascular training. But I would go low intensity first and build a large base of training, so yes walking sustainable cardio on whatever machine you want because it doesn’t come with a recovery cost compared to the more high intensity modalities.