A fool learns from his mistakes, a wise man learns from other's mistakes.

Sorry, it's an expensive lesson to learn but there is too much documentation on avoiding breaches out there for there to be any excuse for this. How can you expect security from an outdated device that has been exposed to a network in the past? You really have to be weighing out your options and understand your attack vectors if you want to partake in this area.

Look into air gapped devices to store large amount of your crypto in the future. Cold card wallet is a convenient solution, you can tell the creators put a lot of thought in all the attack vectors for you.

You're securing your wealth here, out of all the areas you should not be cheaping out or looking for shortcuts this is not where you want to be doing it. You won't be getting your money back, move on. You can rebuild your wealth again but if you don't adapt you will fall into the same pitfalls again and again. Please if you wish to get back into crypto try to play smarter.