I’ve flown both. Here’s what I’d do:
1. Measure my checked bag properly. L + W + H
2. Weigh it properly.
3. If over the allowance, then how much carryon allowance could I shift from my pack to my carryon?
4. If still over, then I have to strongly consider that I’ve got too much stuff. 23kg is about 50 lbs. Do I really need all of it? Shoes are heavy. Could I get by with 1 pr. + flipflops? If I planned to do laundry more often, would that cut the weight significantly? (btw the Purex wash&dry sheets are perfect for travel, in my opinion. They weigh nearly nothing, release detergent in the wash, and release fabric softener in the dryer)

Vueling and Iberia codeshare a lot of flights. Used to be that if you booked it from Iberia, you got a bigger bag allowance. Not sure what’s happened with that in the past year or so since I last flew Vueling, so check it out.

Add Whichbudget.com and Dohop.com to your search. They occasionally pick up an airline that Skyscanner might miss — and vice/versa.

I’ve used both, 3 years ago. Neither were the best of service of the most pleasant flights I have been on but they were the cheapest at the time.
They are very strict with weight limits, I was over but luckily my wife was under so the lady tried charging me at first. After pointing the fact out she unwillingly left some kind of note and managed to avoid extra charges.
I go on skyscanner always,when its a flight I’m after. However I have given up on planes,they are too squashy and uncomfortable for me. I much rather jump on a ferry and the service is a lot better.