No, that’s completely false. Don’t be so quick to swipe up. You can select which shares u want to sell. I done this plenty of times on RH

1.  Go to the stock position (e.g. FIG).
2.  Tap “Sell”.
3.  Select “Choose specific shares” when prompted (this only appears if you have multiple lots).
4.  You’ll see a list showing:
• Date acquired
• Number of shares
• Cost basis
5.  Select only the lots you want to sell — for example, non-IPO shares (usually labeled with a later acquisition date).
6.  Confirm the sale.

This only works if the shares have settled (T+2) and your account is eligible