"BlockedThreadChecker" AND " - Thread Thread" AND " has been blocked"
| parse regex "Thread Thread[.*?] has been blocked for (?<blocked_time_ms>d+) ms" 
| where blocked_time_ms != ""
| fields _raw, _messageTime , blocked_time_ms

// Step 2: Create a transaction around the identified log entry within a +/-1 second window

| where _messageTime >= _messageTime - 1000ms and _messageTime <= _messageTime + 1000ms
| parse regex "io.vertx.core.VertxException: (?<exception_message>[^n]+)" nodrop
| fields _raw, _messageTime, exception_message

// Step 3: Extract relevant details from the surrounding logs
| parse regex "Thread Thread[(?<thread_name>[^,]+),.*?has been blocked for (?<blocked_time_ms>d+) ms" nodrop

| fields thread_name, blocked_time_ms, exception_message, _sourceCategory, _raw

// Step 4: Display the results
| sort by _messageTime

here is above query I am using to get plus or minus 1 seconds from the target log line. no luck so far.
I tried with maxspan event transaction clauses but those are giving me not found errors.