It’s not as convenient as a device like Ledger, but it gets the job done better than any other such device in my opinion.
Just create a seed and some adresses offline and store them securely on a metal plate. Then completely reset the device that you use for creating those informations. Simply store 80% off your bitcoin on those adresses and never worry about anything again. With 20% still liquid you should usually not worry about having to move the other 80% regularly.