You are not looking for permission. You are looking for someone to tell you what you are missing, because you have read the thread so many times it stopped meaning anything.
There are 3 real answers here and only 1 of them is "no".
Free to try. We never store your chats.
If they asked you a question, or left something unfinished, or the last message was yours to answer, the silence is not a standoff. It is just a gap.
Waiting in that situation does not build anything. It reads as distance to someone who is waiting on you.
A message that would be fine at 11am is a different message at 2am, and everybody knows it including you.
Same words, different read. If the content is fine and the timing is not, the fix is small: write it now, send it later.
If they said their piece and stopped, or they asked for space, or the thread has been empty since they went quiet, then a message is not a reply. It is a new demand.
This is the case where sending costs you something, and it is the case people are usually in when they search this question at night.
Who texted last. The 3-day rule. Whether double texting is allowed. These are rules about strangers and you are not writing to a stranger.
What matters is whether this is new behaviour for him. Someone who has always been slow is not sending you a message by being slow.
Paste the thread and it gives you 1 of those 3 answers with the reason, read against how he usually texts rather than against a rule.
If it says hold off, you can still see the drafts. It just tells you first, and it will not pretend today is a good day when it is not.
Try it on your conversation