What is an appropriate sentence for espionage in Ukraine? Questions of proportionality

It is not that often that spies get jailed.  Especially foreign spies.

Most of the time spies are not arrested as most that are known to be thus are inserted under diplomatic cover.  At best they are sent home persona non grata when they are deemed to overstep the acceptable parameters of their spookery per their diplomatic cover.   Most of the time these people are known to be what they are and not what they purport to be by the host nation.