Variables In Execute Commands

I think /execute should have a way to make commands simpler and faster, using variables. Here's my approach:

/execute is already a very powerful command, but sometimes there's things in it you just can't do. What I think Minecraft should add is... variables! Here's a few examples:

/execute as @a at @s var player being entity @s run give Username minecraft:player_head[minecraft:profile={name:player}]

That example command would give you the player who ran the command's player head.

/execute var creeper_and_zombie being entity @e[type=minecraft:creeper] and entity @e[type=minecraft:zombie] run kill creeper_and_zombie

That example command would kill all creeper's and zombie's. This would help you kill multiple with one command without needing chain command blocks or functions.

/execute var special_chest being block 54 128 62 run setblock ~ ~ ~ special_chest

That example command would replace the block at ~ ~ ~ with the specific special chest at 54 128 62

/execute var special_diamond being item diamond[minecraft:custom_name={"text":"Special Diamond"}] run give @a special_diamond

That example command would give all players the special diamond.

 I think this temporary variable system will benefit a lot of people if added! Wether its new people joining the datapack community, people messing with commands, or skilled creators! Clarification: this variable system will only save the variable in the command and wont be like the scoreboard system