Polkadot can't be considered a stable coin. It's different from the real stable coins on which is why they are called "stable" in the first place. The same as other altcoins, it has a speculative price and is subject to crypto-market volatility.

If your fearless research and analysis tell you that Polkadot is a good choice then trust your judgment. From there, now continue to lurk on that coin regularly and see if it makes sense to be involved here for the long term. We have different preferences about what coins to choose that's why we need to take action by doing a self-research and see on the way, if we are in the right direction or we need to shift gears and choose other coins.