Thanks for your wishes.

I staid on Trezor wallet finally. I searched about hardware wallets. And as above informed me Ledger had some issues .

There is another plan after Trezor is that: To buy about 8GB USB flash drive and create it as bootable with Linux OS like for example TailsOS and install Electrum on it. When needed can boot up from that USB stick.

Have this option tested ? if yes is it secure?