This is what I started using about 6 months ago as well. Works good enough for most things around the house. You can upload any documents or pictures relevant to an item as well.

This looks like a awesome organization system app. I may decide to use it in the future for insurance purposes when I move to my own place. But I feel that it is a little bit cumbersome to use for my use case. Thanks for the suggestion.

That looks great for storing documents. However it is not really suited for storing receipts with multiple items and does not really track warranties. Still, good to know about it at least, thanks.

This is the one I have been looking for. It is almost perfect. Even though I didn't want to go the self-hosting way. I will just need to figure out how to deploy it, so it doesn't conflict with Nextcloud (I'm not that knowledgeable). Thank you.

Around 50 receipts + photos of bought items, so it would be around 100 photos. Searching in those photos wouldn't really be feasible and there wouldn't be any relation between photos of receipts and photos of items. Also I don't think I would be able to write all the information from the receipt and about the items anywhere (item description, date of purchase, last warranty date, price, store name, store address).