Samsung S8 slow & Mic issue

[Android Central Question]

Ive managed to speed my phone up in many ways but ever since ive had it , if I have more than two windows opnen the window Im in really struggles does anyone else have this problem?

I use bluetooth in my car and recently when Ive come out of my car the mic stopped working so can only use on speaker, I flukely mamaged to fix once I think through google some how, but now its back to how it was has anyone experienced this or found a solution?

Thanks in advance