OP, I feel that you want to put yourself into some dip shit just for the sake of selling your coins and buy back in the bear market. You don't know where you will
.... expose this your action in future that will make you regret for following this part. If I am in your shoes, I will save myself all the stress and risk of selling to buy back by just leaving my bitcoin in my hardware wallet and continue hodli.
Your idea is illegal in all aspects.
1) I send my crypto assets to the account of my mother in law, who is approaching 80 years old and lives outside of the European Union.
I would let her go through KYC but I manage the account and passwords. I would link her account to my own hardware wallet. I intend to sell most of my crypto by oktober of 2025, and buy back in 1 year later. Once I buy back in, I would send the assets from her account back to my hardware wallet.
Let's say you live in Spain and your mother in law live in Thailand, if you access her account when you're in Spain, the exchange will detect there's a suspicious activity since a Thailand account get accessed by Spain IP address.
If you use VPN, you broke the exchange terms.
It doesn't matter, the exchange might not be concerned about that if he doesn't use the account in a suspicious way. My friend mom was the one that opened his Binance account for him abroad, she gave him the password after all KYC has been done, and he uses the account. The only thing is that it is not your account because you can be deprived access to it at anytime.