Thanks.
Writing the transaction to the DB would involve a new table, for the reasons discussed above. The wp_wallets_txs table is for user transactions.
If you are planning to create a plugin to handle and report stake rewards, it is best if you create your own table or structure to store this info.
You can use the existing actions to intercept incoming TXIDs, or use your own mechanism altogether. In any case, this feature is out of scope of this plugin.
with regards