Your toddler suddenly hates diaper changes as they are learning that doing other things is more fun.
You can try making the diaper changes more fun for your toddler by singing silly songs, making a game out of it, handing the toddler a clean diaper and wipes to help.
Or you can also give the toddler a toy to play with that they only get at diaper change time.
You may also try changing the toddlers diaper wherever they are instead of picking them up and removing them from the area they are.
If your toddler is standing and it's only pee you can try doing a standing diaper change which most toddlers will be more happy with instead of laying down.
It's very normal for toddlers to suddenly hate diaper changes and most toddlers will stop having diaper change tantrums eventually.
My 8 year old son when he was a toddler started fighting diaper changes around 13 months of age and then finally stopped around 2 and 1/2 years old.
He was potty trained almost before his 4th birthday.
If the toddler is old enough to potty train then the hating diaper changes can be a sign of potty training readiness although it's not always the case.