Seems Stake is just being rather cautious on it due to their US broker dealer - DriveWealth. They apply it to all accounts below 25k in value as stated in their help, but you can get around it by depositing until you have more than 25k in value:
Exemptions from PDT
Restriction on day trading only apply on account values under $25K, regardless of whether you’re on Stake Black or not. Those with account values over $25k can day trade freely, without restriction.
What if I’m marked as a Pattern Day Trader?
If you are ever marked as a Pattern Day Trader or getting close, you can fund your account above $25K to remove the restrictions. However, you must be able to maintain this account value for the duration of the initial flagged 90 day period.
Stake Day Trade Counter
To keep our customers safe and on the right side of the rules, we’ve built a Day Trade Counter into Stake. This will keep track of all your day trades and notify you when you are on your third day trade in a rolling five trading day period. You’ll always have the right (and given the choice) to make a 4th day trade, but will be warned of the impact this may have.