Total noob with noob questions

Hi everyone,

I’m a total noob looking to buy ETH and BTC for the first time. I first learned about BTC in 2011 when it was still super fringey and almost bought but didn’t. I’m now kicking myself and don’t want to make that mistake with ETH and the upcoming crypto/blockchain decade.

My strategy: I’m looking to invest $5000 in ETH and $5000 in BTC and HODL everything for ten years. I’m also thinking about adding $5000 a year into each for the next ten years.

Storage: I just bought a Ledger wallet and a steel seed list. I’m wondering:

1. do people keep a backup of their seed list so that if you lose it you have a copy? Any other strategies with seed storage?

Gas fees: do BTC and ETH charge gas fees? How do I check what these are? Sorry for the super basic questions. I just want to know what all associated fees are and how to account for them.

Are there any other hidden fees? I’m aware of CGT but would there be any other gotchas or transaction fees I should be aware of?

Is the best strategy for a noob to just use Ledger Live (and I believe Coinify?) to buy their crypto?

Thanks I’m advance and I really apologize if some of my questions seem a bit scatter brained - I’ve binged a ton of videos over the past week and am still getting my head around everything.