The reason is fully justify in case of war , China needs to have 8 Destroyers available on CPEC port and the best solution is a Grant to Pakistan of 8 Destroyers to safeguard any illegal trouble makers
China has to protect the China Southern Sea
and now also has to protect Western Gawadar port
And it would be easier if Pakistan maintains 8 destroyers
To help ease the burden of looking after CPEC
Also the destroyers would help , against any illegal Battlistic missile coming from unwanetd nations
Really in both Russia / China's interest
Russia wants to sell oil and China has lot of trade
Lease for 30 years would be also realistic figure
This would be a ideal choice 8