If someone will get access to my Coinomi wallet on Android 10 they can get access to my private keys?
If they gain access to your coinomi wallet, i.e. access to the wallet application on your device? Then definitely, yes.
I mean if this someone have understanding of situation and get access full hardware access to my Android 10 smartphone storage.
That's a tough question.
The storage is encrypted, by default.
If you have an older model, some vulnerabilities
might exist which allows to extract the master key.
If the device is running (and decrypted) when someone gains access to it (i.e. it is booted and has been unlocked once by you), then a cold-boot attack might be possible where the whole device is cooled down, memory extracted and then directly accessed.
The latter one is a sophisticated attack and not achievable for a random person.
In general i'd say you are fine if the mobile is turned off. If it was turned on, the risk is higher but still low enough to not completely freak out if you don't store tons of crypto on it.
Definitely make sure to never use these keys again tho and move your funds away as soon as possible.
Don't store more money on a mobile wallet than you would carry with you in cash, and you are fine.