1. You are right, /summon item ~ ~ ~ {Item:{id:"minecraft:loom",Count:1b,tag:{display:{Name:'{"text":"Hi"}'}}}} does work when it is put into a command block. But (as far as I know) it doesn't allow you to run the command when you are trying to run it from inside a command block you are creating in the original command. When you are using the "Command:" tag. It makes you use \"--\" instead of "--", I think so it can easily know the difference between the actual command and the command in the command. In other words, the command block minecart causes it to not work. That means that when I do just use ". It won't run
summon minecraft:falling_block ~ ~.5 ~ {Time:1,BlockState:{Name:activator_rail,Properties:{powered:"true"}},Passengers:[{id:command_block_minecart,Command:"setblock ~2 ~0 ~-1 repeating_command_block{auto:1,Command:\"execute as @a at @a[nbt={Inventory:[{Slot:100b,id:"minecraft:netherite_boots",tag:{display:{Name:'{"text":"Jump Boots","color":"red","bold":true,"strikethrough":true,"obfuscated":false}',Lore:['{"text":"MOD TOOL","color":"gold","italic":true,"bold":false}','{"text":"12345678910","color":"black","obfuscated":true}']}}}]}] run effect give @s minecraft:speed 1 5 true\"}"}]}
2. I am not using a data pack because I don't know how to make a data pack and I don't use commands enough to learn.
