[2023] I unlockt Rang VII cant Play Rang VIII

Hello

If you hover over the F.3 or GR.1, it will tell you how many vehicles of the previous rank you need to unlock in order to access that rank.

As an example:

You have access to the Harrier GR.7 as you obtained this before the Rank rebalance post Apex Predators. As such, you will need to research the required number of vehicles to gain access to that rank.