after updating my world the world bugs out

i didnt see that 1.21.4 came out so i didnt know my version got updatet,

so i went into my world and bc there was no sign of a new version i didnt relise it.

 

i was in the nether at my farm and the world startet lagging, so i went in the overworld and the game just froze, i can still move around but nothings loading. and there are no ticks.

 

this happens every time, bc i didnt do a backup(bc i didnt know of the update) im now set back abouut 50 hours(if i use my old backup)

is there some way i can set back my game(version)without reloading the whole world?