No muscle pain, but exercising to failure. Am I doing something wrong?

I'm quite new to all this, doing upper body workouts at home for a few weeks now.

I never have any mentionable muscle pain, except a bit in my triceps. And if I do normal crunches in my abs. Sometimes I feel a bit stiff or a barely noticable muscle pain. I find that strange and it makes me wondering if I'm doing something wrong.

I do take creatine and I do exercise to failure everytime (e.g. with pullups I can not do another one. And for the biceps for example I stop when my arm gets shaky and I don't have proper form anymore.)

My questions / hypotheses are:

1. Can I do the same exercise every day if I don't have sour muscles? Or do they really need to have a restday in between? (I like to do the exact same exercises around 5 times a week)

2. Do I need to do more of similar exercises? E.g. not just 3 sets of push-ups, but also 3 sets of wide arm push ups, etc. The same for biceps, dips, etc?

3. Do I need to just give it more time because I've some weaker muscles that 'hold me down'?

Thank you for taking time.

P.s. my Workout (which takes around 45 min, with 3 sets of 8-12 reps and 1 min pause between every set):

Pull up sets (with cord)

Dips

Australian Rows

Push Ups (20-15-10)

Biceps

Leg raises

Planks

Side Planks

(My legs have always been trained with other sports, training my upper body is new. For now I train my legs 2-3 times a week with cycling and racketsports, just want to get some momentum in upperbody first before I rebalance things)