Behind with behind on

In this video game, you need to upgrade your troops so they become stronger.
How would you say the following

I'm behind with my archer upgrade.
I'm behind with up gradins m'y archer.
I'm behind on my archer upgrade.
I'm behind on upgrading my archer.

In the game the higher your level the stronger your troops need to be so if you don't upgrade them as your level increases, other players will be stronger than you. How would you say the following? Is it correct to use 'in relation'?

As long as you don't fall/aren't behind with/on upgrading your troops in relation to your level, you'll be fine.
As long as you don't fall/ aren't behind with/on your troop upgrade in relation to your level, you'll be fine.

Don't be behind with your upgrades and you will be fine.
Don't be behind with upgrading your troops and you will be fine.

Which is correct please?
You need to upgrade your troops as your level increases.
The higher your level, the more you need to upgrade your troops.

Thank you for your help