The Bitcoin network is open to the public. You can check any transaction status if you know its Transaction ID, sending or destination addresses. To see your SOL BTC receiving address - check Topup/BTC menu of SOL app. To find Transaction ID of BTC withdrawal from SOL - check the transaction receipt in the BTC account history (available in 30-40 minutes after transaction). Then you can use that transaction ID to check if it is confirmed and reached your recipient already.