You can tell 1krBlocker whom you trust and whom you never want to hear from. Open Settings → Trusted & blocked senders. It has two tabs, Trusted and Blocked.
Trusted senders: messages from them aren't treated as unknown. Their links are still checked, because trusted senders can still send dangerous links if their phone or account is misused.
Blocked senders: their messages go straight to Blocked in Quarantine; you won't be notified.
To add one: tap Add a trusted sender or Block a sender, type a phone number or a sender name (such as "InPost"), or tap Choose from contacts. You can add a label, for example "My bank".
Faster, from a message: open a conversation's menu and tap Trust sender or Block sender.
Block on the whole phone: with Also block those numbers on this phone turned on in Settings, numbers you block are also added to Android's own block list, which your phone app uses too, so their calls are blocked as well.
Unblocking: tap Remove next to the sender on the Blocked tab. If you see "Removed …. It is still blocked by your phone’s own block list, which 1krBlocker doesn’t change.", the number is also on the phone's own block list (added there by you or another app). Remove it there: in your phone app's settings, under blocked numbers.
To block every number that starts the same way (for example all numbers from one country), use Block a range of numbers….