Plus one for the grout removal tool in the last video. Mine was from screwfix or toolstation and came with two blades. A thin one and a thicker one with some sort of abrasive grit stuck to the edge of the blade. Be careful wiht the grit attachment as it will mark/chip the tile edges if used in anger
I tried one of the grout removing hooks but managed to rip the edge off the first tile I tried to remove . So I used a vibrating tool with a diamond impregnated half disc . Took out 48 , 75 mm tiles in the kitchen without breaking any and reused all of them .
First I cut the edge grouting out to the tile sides then took one tile at a time off using a long off set leg 19 mm blade to cut the plaster under the tiles , once the tiles were free I used the diamond blade to buzz them flat & clean . Then replastered the damaged area .
I noticed the tiles that had been used had tiny bobbles that in effect matched up to the adjacent tile and gave space for grouting . Using the diamond blade took them off so I used card board strip cut on my photo hobby guillotine
Thankfully I'd purchased three sets of extra blades from Aldi … "Workzone " brand .. they were brilliant I only needed to replace the diamond disc once as it had worn smooth by the time I got to doing the last few clean ups.
I have found that after removal, soaking the tiles in a bucket of water overnight or a bit longer usually softens the old grout enough to scrape it off. Then so much easier to reuse.