You are not stuck because you cannot write. You are stuck because every version you draft is carrying too much.
Here is what to leave in and what to cut.
Free to try. We never store your chats.
Most drafts have 2 things in them: what you meant, and what you would take back in the morning. The second one is usually the last line.
Read your draft and find the sentence that is there to make them feel something. That is the one to delete. What is left is usually the real message and it is usually shorter than you expected.
A message that can be answered in 6 words gets answered. A message that requires them to account for the last month does not.
This is not about being casual. You can say something serious in a way that does not demand a serious reply back immediately.
"Why did you stop texting" and "I noticed you unblocked me" both put them on trial in sentence 1.
If the silence needs to be discussed, it gets discussed after they are already talking to you.
The message that works depends on how you actually talk. A warm, light version and a direct, firm version can carry the identical point and land completely differently coming from you.
If it does not sound like you, they will hear it. People know how you write.
Paste the thread and it gives you the message in 4 tones, plus your own draft cleaned up — the part you meant kept, the part you would regret cut, and 1 line on why.
It also tells you whether tonight is the right night to send it.
Try it on your conversation