How to CODE YOUR OWN CUSTOM POTION EFFECTS with ONLY 1 command easy and simple (java) (1.17.1)

/give @p cyan_shulker_box{BlockEntityTag:{Items:[{Slot:0,id:repeating_command_block,Count:1,tag:{BlockEntityTag:{Command:"/scoreboard players remove @a[scores={POTION=1..}] POTION 1",auto:1b}}},{Slot:1,id:chain_command_block,Count:1,tag:{BlockEntityTag:{Command:"/execute at @e[scores={POTION=1..}] run particle minecraft:item_slime ~ ~0.8 ~ 0.2 0.3 0.2 0.1 10 force",auto:1b}}},{Slot:2,id:repeating_command_block,Count:1,tag:{BlockEntityTag:{Command:"/execute at @e[scores={POTION=1..}] run execute as @e[type=#arrows,distance=0..3,] run data merge entity @s {Motion:[0.0,-2.0,0.0]}",auto:1b}}},{Slot:3,id:oak_sign,Count:1,tag:{BlockEntityTag:{Text1:'{"text":"manual commands","clickEvent":{"action":"run_command","value":"scoreboard objectives add POTION dummy"}}',Text2:'{"text":"RIGHT CLICK ME","color":"yellow"}',Text3:'{"text":"ONCE","color":"yellow"}'},display:{Name:'{"text":"Custom Sign"}'}}},{Slot:18,id:repeating_command_block,Count:1,tag:{error:"Expected string to end with } or ]"}}]}} 1