I use cubase mainly for recording and composing using midi keys. Sometimes I create some short multitracks (and master them), though it is relatively rare.
I have Cubase 9 pro. Should I move to Cubase 10 or there is nothing which I can not handle without? Thank you!
Might as well wait until Cubase 11 comes out. Usually around November/December.
If you are not capable of deciding that yourself, you donˋt need Cubase 10.
From your description of how you use it, your money is probably better spent on something else. The multi tap delay in 10.5 is really good, but many of the new features you probably will hardly notice.
Look at the list of What’s New in Version 10 (and 10.5 too). Do any of the things listed sound interesting or useful to you? If not stay on 9. If so, is it useful enough for you to pay the upgrade price?