Silent payments sync issues: BTC in the void
**Describe the bug**

Silent Payments seem more like an alpha feature than a tested feature for release. These almost never sync, sync hangs forever at the first block most times, and when they sync it seems to not detect all payments correctly.

I have a wallet where I received a silent payment. At first, it was detected after trying the sync feature a dozen times, one of the times it clicked and synced so the payment appeared (note there are 5 TX, the **number 1** is the one recevied via SilentPayments (amounts and timestamps have been redacted from the images):


<img width="450" src="https://github.com/user-attachments/assets/b7d41e49-668e-4c42-88f8-6ca389e99996">


Then, after a while, I can't send any BTC to anyone, since an error message appears saying `Exception: Cannot find private key`. This happens when I try to send any amount of BTC to any BTC address:

<img width="450" src="https://github.com/user-attachments/assets/8764d4b2-69f6-43b0-9d8a-0d91e42c37bc">


Now my wallet is totally locked, I can't use my BTC at all. After many attemtps to send, I decided to install Cake Wallet on destkop via Flatpak and reimport the wallet, I did it and the **non-SilentPayments** BTC appeared, but the ones received via SP address do not appear (note TX **number 1** is not there, and of course the status of the wallet is `Synchronized` with the SP scanning finished too):

<img width="450" src="https://github.com/user-attachments/assets/c41a4f07-ea74-423d-8d3b-913ca8bd1f24">

I assumed it was because it needs dedicated scanning of SP transactions. I know the exact block where I received the TX so I scan one block (since scanning all blocks is very, very slow). It scans and nothing appears. I try again, like 10 times. Nothing.

Ok, so I try to scan from 10 blocks before the TX was received until now. I wait for like an hour for around 3000 blocks to sync with SilentPayments. Nothing.

So it seems like I lost some payment in the void, which I obiously need and want to recover at all cost.


**Expected behavior**

Silent Payments sync correctly and appear.

**Platform:**
 - OS: `Android 14 (GrapheneOS)` // `Fedora Linux` (Flatpak version)
 - Device: Pixel 8 Pro // Average Laptop
 - Cake Wallet Version: `4.1.19` // `1.9.0`
