Securuty and performance problems

How to fix this nextcloud security and performance problems?
(The memory cache error was almost fixed, but the redis bug was dropped to make “redis server version old, something 3… and new can not install”.)

(Sorry for my english!)

Read the documentation? The issues are all spelled out there, with links on how to fix it…

I read, tried but no improvement. That’s why I was thinking of getting some more specific instructions here.