Welcome to the forum.
When you checked the transmission fluid level, what color was the fluid? What did it smell like? Bad fluid looks almost black, smells like burned brake shoes. Good fluid is bright pink, with a very light mineral oil smell.
Go to the 3 dots next to your avatar, click & do an Advanced Search for transmission fluid replacement. Fill in all your vehicle parameters & hit switch. You'll find a wealth of real world knowledge from folks who have had the same problem as you describe. More importantly, you'll discover what they did to correct that problem.
Honda does a great disservice to its owners when using the term "flush" in its transmission service procedure. Honda DOES NOT recommend attaching an automatic transmission fluid flush machine to your vehicle & do the reverse flush method. Tolerances inside the Honda transmission are such that machine flushing will push contaminated bits into parts of your transmission, affecting its operation. Too much contamination & you are in for a complete transmission tear down & rebuild.
The recommended transmission service for Hondas is to drain out the old fluid & refill with new fluid. Make sure you have added enough new fluid to show between the 2 marks on the transmission dipstick. Drive around for several miles, then repeat drain-fill-drive 2 more times. After the 3rd drain-fill-drive procedure, check your fluid level & top off if necessary to get to the top mark. This method replaces about 90% of the old fluid with brand new fluid. Many Honda transmissions have gone well past 250KM just by doing this procedure every several years.
Do-it-yourself transmission fluid exchange is not that difficult. Just be sure you have enough of the correct transmission fluid on hand before you drain out the old fluid. Old fluid beats no fluid every day of the week. The drain-fill-drive is a 1 person job, providing you can get under the vehicle to reach the drain plug. The fill plug is the dipstick hole.
If you have competent help, and are feeling more adventurous, you can do a complete fluid exchange through the transmission cooling tubes. Several YouTube videos out there showing you how to do this. Be forewarned: this procedure has its risks, the most damaging being running the transmission without any fluid in it. GREAT BIG MISTAKE. Again, only try this if you have competent help. THIS PROCEDURE IS NOT A 1 PERSON JOB.
Good luck & keep us informed.