I have been running Bitcoin core wallet for a while on my mac (1TB HDD) and recently started noticing that the Mac has gotten too slow.

Few hours ago, I couldn't do much, waited ~10s for keys to respond and programs took longer to open.

I checked the disk partitions and noticed that there was just less than 100GB of space available.  The "others" folder which is where Mac stores junk, unclassifiable files and application caches was large.

I had to uninstall Bitcoin, after uninstalling BTC, I noticed that the space was still occupied. Apparently, uninstalling Bitcoin core doesn't remove the downloaded blocks.

Looking around you will find that the Bitcoin data is in this folder

ls ~/Library/Application\ Support/Bitcoin/

banlist.dat chainstate peers.dat
bitcoin.conf debug.log wallets
bitcoind.pid fee_estimates.dat
blocks mempool.dat

Easily run

rm -rf ~/Library/Application\ Support/Bitcoin/

voila, all Bitcoin data gone from your Mac!