Blundering a lot out of absolutely nowhere, why?

Samples from today...

won this one but feel I could have been more surgical and less sloppy

Do you see a common denominator, a weakness I could work on, or am I just fried and needing a break?

I should go back to doing them regularly. I forgot and then lost the habit of doing them.

I've blundered that queen battery mate in game one before. I just had to laugh.
Maybe look for that more.

You play too fast.

What I saw is that you play 10-minute (which is almost certainly not enough), and you don't even use that. For example, move 9 in the fist game was an obvious moment to spend some time and find a good move. With all those nasty discovered checks possible, there has to be something. But you thought "nah, let's just play some random move in 10 seconds".

It happens

Use your time, you are given 10 minutes to think about your moves, use them

Stop playing fast time controls they are a blunderfest and play a longer one where you have enough time to double check all moves.