Photoshop 21.1 running very slowly

I am feeling guilty already, bc I am writing you to ask how to incorporate brushes back in to my Photoshop.

After 2 days tech support for other issue (Mac + Catalina) that was resolved but my brushes vanished. I don't know how to find a link to get them back ! Yes I tried tutorials but to no avail. I am a senior/so require patience for sure...I had brushes for grass, and glitter/glow and a full array but now just a very few and none I know.  I looked at Adobe site and one can buy some for 30$ a month, but I don't need that I know how to create the glitter like a halo on an angel, myself.  Hope I have not made you angry ! Cynthia

Two things to try noticing your screen shots.

Try these one at a time to see if it improves.

1. Make the Drobo your scratch disk and promote to primary. Restart Photoshop.

2. Turn on Legacy Compositing. Restart Photoshop

Hello all, there's been some behind the scenes changes that can affect the interactions with Photoshop, please be very specific on which operations are slower, how you perform them (shortcut, tool, menu...), please give some info about your setup, and once replicated by others, please search or create a thread on the https://feedback.photoshop.com site, watched by Adobe staff. Make sure to provide as many relevant details as possible (OS version, GPU drivers, exact procedure used to perfom a given task). They won't be able to fix one tool if they just get a "Photoshop is slower" feedback. Even though they also perform some tests, there are so many ways to perform an action in Photoshop that it is impossible to test every interaction possible.

I've just updated and instantly got performance issues, in my case all real time previews for i.e. direct Hue and saturation take almost 2 seconds to show on screen. It's annoying indeed. I downgraded to the previous version and it's all working fine, BUT it reset all my presets to DEFAULT. Not sure if there's a way for me to load everything as it was before, so that's also really annoying.