Great to have you here, Tom. Just practice and be patient. Your technique will come around.
You are going to need a lot more than 10 shaves before you can start detecting the nuances of the hardware. I would stick with one blade (brand) and focus on technique for a while.
Some blades don't work well with some people, but, here's the kicker. You have just started, and your technique will improve greatly, over the next few months. Revisit the Astras in a few months, you might have a change of heart.
Good face preparation, and a shallow, light touch, with the razor.
Remember, ATG shaving can irritate the face on some.
Welcome Tom; The first shave with a new blade does not predict future results. Put the Astra SP's aside for now and go back to the ones that worked for you and stay with the same razor/blade combo for awhile and let your techique improve and it will.