I don't think anyone is likely (or even required/well advised) to mention on a c.v. that your contract was P2F. I think it is sufficient to merely state the fact that you only worked there for such a short time ,as that was the duration of contract offered.
Much more problematical is only acquiring 300hrs on type, as 500 is usually the absolute minimum for most airlines looking to employ you on a subsequent short term contract.
Of course airBaltic may take you back next summer, but more likely they will prefer to take someone else on reduced wages for the period and put another 300hr pilot on the market.
With the rate of departures on this fleet there remains a small chance the contract will be extended over winter, but it will certainly only be for a few, and not everyone.