I feel your pain! I'm struggling with chord changes too. But I like Moe's suggestions of making the chord clean and getting a good tone.
I am working on songs with G, C, and D in them. There are some in the song library and songbooks you can find elsewhere that just have a few chords in them. Amazing Grace is one of them in the song library here. https://www.guitartricks.com/lesson.php?input=19335&s_id=1490 The Made Easy songs are great to check out, too.
I'm hoping that by focusing on these three chords and switching between them that it will help me out with the other chords too, just by getting used to the motions. I also do some 1 minute changes sometimes, too. Set a timer and go as fast as you can and count how many you can do, strumming each time (once). Don't worry about getting a perfect tone, just get your fingers on the strings...tone will improve once you get used to changing chords quickly. (Just a tip I've picked up along the way and I feel it's helping me.)
Good luck!
“Often, what seems like an impossible climb is just a staircase without the steps drawn in.” Robert Brault, American Operatic Tenor