If you lost a significant amount of gear, I would enable console and replace those items in a separate world from the one you play on. I have had this happen, but luckily I only lost a few consumables and didn't need to respawn anytyhing.

https://valheim.fandom.com/wiki/Console_Commands

https://valheim.fandom.com/wiki/Item_IDs

I wouldn't spawn anything other than the items you need to replace and the materials needed to upgrade them to the level you had them at, otherwise you'll just ruin the experience