Unity IAP DLC + Gameflow Inquiry

[adobochad]

TL;DR: Is there an efficient way to have a DLC setup where you can select between multiple levels and the first level selected and completed is free, and upon the first level completed, the other levels become purchasable as DLC.

Hi all, I'm currently using Meta Horizon Developer Dashboard to manage In app purchases and DLC. Looking to get some 

We have the following work-flow, and we're not sure if this would be supported/plausible in some capacity:

I have 3 levels that are all DLC, however the first time you play the game, we want the first level you select is free to play/test/try etc and then once you complete that level, all the DLC is available for purchase, but now you have to purchase levels since we've completed the first level.

However, the constraint is that since we've selected a level for the first time, we always want to have that level available to us to play. There's also the potential we might want to scale this to 10+ levels, or some arbitrary amount of levels, so I'm not sure if having the levels already in the build will make sense.

Example wanted workflow:

Level_A, Level_B, Level_C -> All DLC, but one of these will be free upon first selection/playthrough.

1) User selects Level_A as their free trial and are able to play through this level entirely.

2) User goes to our level select menu, it should have the following options: Level A is purchased and ready to play, Level B and C need to be purchased.

I think I see two potential ways to solve this, but I'm not sure if either are viable.

1) In our DLC content page we have a free DLC version of each of our levels, and our first UI will let us download and select the SKU of the free DLC asset. After our first level, we enable another UI that has the SKU's of the available levels to purchase+ the free level we have initially selected. 

2) The levels are packaged into our game, but they're gatekept behind DLC purchases. For this example, if this is the player's first time, we can just select and load any of the three levels as normal, but the next time the player selects a level, this will be gatekept behind validating the level purchases. However, just like the first solution, we will have to keep track of the first level they selected and we don't want to allow that purchase again. (This also might only work if we start with these initial levels?)

With both solutions, it seems we'll need to securely store two variables, the player's free level they have selected AND the player has played through that first level. If this part is not done properly, a player could attempt to spoof playing the free level, and also do it again for subsequent levels. This is truth for both noted solutions above. 

Just wanted to write up and see if this is a vilable strategy, and if not, what is an alternative approach to this level selection with DLC? Thank you!