For a beginner, don't worry as much about intensity but more about distance. You should make a rough plan of gradually incrementing total miles ridden per week until you're at around 80+.

At that point, speedwork with intensity is worth doing. Until then, you will gain more from accumulating distance.

I'm riding about 140 miles per week now, and have made steady progress despite not being a beginner, and riding almost all my bike miles at 'easy-moderate' (can still hold a conversation albeit somewhat out of breath) pace and never really pushing it to that red pain threshold. I used to ride until I felt like blacking out, but I'm honestly making better progress with the long slower mileage accumulation that ratchets up every week. It's still hard - you'll be pretty fatigued if you're doing the buildup right.