Self custody wallet planning for stacking (now) and spending (later)

How should one go about with self custody for stacking and eventually spending it?

We know people strive to become a whole coiner (or get as much as they can) and lets assume they are DCAing thro an exchange or app like strike/swan now. How should one go about self custody? Below is what I think and would love your tips/suggestion to make this better.

1. UTXO consolidation Accumute sats in exchange/strike like app and once it reaches X amount, withdraw to self custody.

This X amount is not fixed. We should have UTXOs in all ranges, like a few 1 million, a few 2 millions, a few 5 millions, a few 10 millions. Need to keep an eye on how this goes down the line. If fees are getting so high, it is good to consolidate the 1 millions to 2 or 5 millions in a few years. Don't do that in a high fee environment. Like btc price, fees too have a high and low cycle and do that consolidation in a bear market while fees are low.

2. Have atleast 2 hardware wallet Once you reach a substantial amount, like say 0.3 or 0.5 btc, buy another hardware wallet, from a different company, and start accumulating there.

3. Always use a passphrase along with 24 seeds. All wallets calls this as advanced feature and I don't know why but I think this is must have and a basic security feature we cannot afford to miss. Also, 24 seeds words should be written down in paper/metal plate but the passphrase should be remembered. So though you can have multiple words for passphrase, use what you can remember and recollect easily. Once in few days/week, remind yourself of the PIN and passphrase you used.

4. Is multisig necessary for, say, 0.5 or 1 btc? I am not sure and this is something people can pour in their views. It is a complex process and whenever I read about it, the feeling I get is, most people are better off with passphrase/seed words than a multisig configuration.

5. Once every year or so, try resetting the hardware device and load it back with same account. This way we make sure our passphrase and seed words are correct and intact. Do one device at a time

6. Keeping seed words in metal plate, not to enter seed words in any device other than hardware wallet, keeping wallet firmware up to date, not talk about your btc balance to strangers, not using lending platform like celsius, not keeping in exchange for long etc.. all goes without saying.

Pls add any more tips/suggestions, for the stacking phase.

Now on to the spending/selling phase. Here is where I need help.

Let's say down the line 10 or 15 years, our stack has grown substantially and we plan to live on bitcoin or sell some to buy a car/house, how should one go about this? What he needs to do from now on, so that the selling phase is smooth and less expensive?

Should one set up a self custody lightning wallet now itself, when fees are not that high (as compared to fees in 10 years)?

How much balance should I keep in there? And will it be as safe as balance in hardware wallet?

Should I have another self custody lightning wallet, just like hardware wallet, to spread risk? Like have both phoenix and breez and have a million sats in each?

What other things I should do now, to make sure the selling/spending phase is smooth?