This type of post is always interesting.

Don't you think that having MULTISIGNATURE in a wallet that only you will use is a bit complicated? You even had difficulty with one of the signatures and that delayed your management of the UTXOs. Using a cold wallet is quite safe, so is using the OnlyWatch wallet. Likewise, instead of using a single wallet, use several and separate stashes.

The size of the UTXOs will always depend on their purposes. I even think that @DarthCoin's recommendations are good practice, using several wallets with different purposes. It would be a wallet for Holding, a Wallet for Cache with which you finance the channel, a node you do LN/Onchain swaps; and the spending wallets, preferably Lightning, for daily, weekly expenses, etc.

And finally, I have seen that mining fees have been around 2 to 3 SAT/vB. So always waiting will have good results.

Thanks for sharing your experience. Successes