Updated:

1. Give the kit once

# Repeat, Always Active
give @a[tag=!got_kit] minecraft:stone_sword
# Chain, Always Active
give @a[tag=!got_kit] minecraft:bread 16
# Chain, Always Active
tag @a[tag=!got_kit] add got_kit

tag=!got_kit means players without the tag. The last block adds it, so the kit is given only once. Add more chain blocks before the tag block for more items (tag command).

2. Equip armor directly

item replace entity @a[tag=!got_kit] armor.chest with minecraft:leather_chestplate

Slots are armor.head, armor.chest, armor.legs and armor.feet. Bedrock uses /replaceitem (item replace command).

3. Re-give after death (Java)

scoreboard objectives add deaths deathCount
give @e[type=player,scores={deaths=1..}] minecraft:stone_sword
scoreboard players reset @e[type=player,scores={deaths=1..}] deaths

Run the last two in a repeat and chain block. @e only selects living entities, unlike @a, so the items arrive after the player respawns. To simply keep items, use keep inventory.

4. Reset the kit

tag @a remove got_kit

5. Many items

Give one filled shulker box instead (shulker box items).

Troubleshooting

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