That is some cool anticheat/manipulation for sure.
The risk you run with no pay-to-win is the hardcore gamers not wanting to get in if it is not first day. That feeling of being left behind and underdog don't work well with powergamers. There should be some later stage entry that enables people not in on day 1 to catch up a little for their experience, game lifespan, and money coming back to the development team to keep innovating. You probably have this all planned out though.
It can be partial, as you may have noticed we're not too "moneyhungry" probably to a fault, like, new players can join and at some stage in the game's progress they may not need a vial at all but can purchase "second hand" healers and creatures to play the game with. There may be a small fee to prevent abuse, similar to splinterland's spellbook requirement, but point is new players may only face the level requirements so they'll be forced to buy a lvl 1 healer and creature but not necessarily through us and instead through the market from other players who bought many vials or put up creatures they captured on the market. I.e. you won't need a starter creature to start playing at some point in time but you will need 1 creature at least and a healer, if you mint them directly and pay us or buy from the market from other players is fine by us as long as you buy something. This helps bring back additional value to player's assets long-term.
Eventually they may also be leasing and trial period "spellbooks" as well.