If by master you mean factory reset then I would if I were in your shoes just to rule it out. It's unfortunate but people should be aware by now it's somewhat common for these thinks to happen on a big upgrade. Incremental upgrades you don't necessarily need to.
My A7 is running just as fast as before. I've had a number of high end phones, but the A7 is my favorite. In the past I've had a
LG V10, galaxy note 4,galaxy S6 edge, galaxy S7 EDGE, and pixel. The worst one of the bunch was the V10. Very bland screen, poor battery life, and so big and bulky too. After that my pixel only lasted 3 weeks before I knew it was absolutely nothing but a ripoff. I kept my S7 edge because it does everything that I want in a phone except good audio. The A7 has the best audio, and matches the S7 edge on everything else except the curved screen. But the quality of the screen is the same.
Yeah, my phone slowed a bit when I updated, especially fingerprint unlocks seemed laggy, and notifications were sometimes wonky. I did a factory reset and was back up and running 30 seconds later with a snappier phone. Highly recommend it.