The main problem isn't even the big size of the blockchain, downloading or storing it (which is a problem), but the actual validation of increasingly complex blocks due spammers.
Check the charts:
https://statoshi.info/d/000000009/unspent-transaction-output-set?orgId=1&from=now-5y&to=now&timezone=browser&refresh=10m

If you go there you'll see that when the Ordinals protocol started and all this nonsense became popular (Ordinal Punks, Taproot Wizards, Bitcoin Rocks, etc.) followed throughout Jan–Feb 2023 and into 2023+ you'll notice it becomes increasingly difficult for the node to validate blocks.

"Size of Serialized UTXO Set" is the total disk size of the serialized Unspent Transaction Output set (UTXO set) and so when you are syncing the blockchain, specially if you are using a non-infected computer (a computer from 2008 or earlier, without an NSA embedded OS such as Intel ME) then it will become a nightmare to sync it as it will struggle to process those blocks.

Bitcoin Core v30 will only make this worse,  which is why the logical conclusion is that Bitcoin Core v30 is a de-facto attack on the network and Knots 29 is the only thing we've got to corner spammers into irrelevance (and not to mention the whole CSAM-on-the-blockchain attack vector as well)

As far as the backup, I would backup everything, but for a sanity check, I like to generate fresh chainstate files when running a brand new backup. The problem once again is, it's becoming a nightmare to do so on any useful laptops you may have. You pretty much need a gaming computer these days to verify the full blockchain. This is a disaster when it comes to running Bitcoin with maximum security.

The main problem isn't even the big size of the blockchain, downloading or storing it, but the actual validation of increasingly complex blocks due spammers.
Check the charts:
https://statoshi.info/d/000000009/unspent-transaction-output-set?orgId=1&from=now-5y&to=now&timezone=browser&refresh=10m

If you go there you'll see that when the Ordinals protocol started and all this nonsense became popular (Ordinal Punks, Taproot Wizards, Bitcoin Rocks, etc.) followed throughout Jan–Feb 2023 and into 2023+ you'll notice it becomes increasingly difficult for the node to validate blocks.

"Size of Serialized UTXO Set" is the total disk size of the serialized Unspent Transaction Output set (UTXO set) and so when you are syncing the blockchain, specially if you are using a non-infected computer (a computer from 2008 or earlier, without an NSA embedded OS such as Intel ME) then it will become a nightmare to sync it as it will struggle to process those blocks.

Bitcoin Core v30 will only make this worse,  which is why the logical conclusion is that Bitcoin Core v30 is a de-facto attack on the network and Knots 29 is only thing we've got to corner spammers into irrelevance (and not to mention the whole CSAM-on-the-blockchain attack vector as well)

As far as the backup, I would backup everything, but for a sanity check, I like generate fresh chainstate files when running a brand new backup. The problem once again is, it's becoming a nightmare to do so on any useful laptops you may have. You pretty much need a gaming computer these days to verify the full blockchain. This is a disaster when it comes to running Bitcoin with maximum security.