In this day and age, considering the power available from amplifiers, no one should still be using 1/4" phone plugs to connect between amplifier and cabinet. Never ever use an instrument cable for this duty!!
I've been using rack pre-amps since the early eighties when I built my first SS power amp. Since then I've enjoyed a few different units, some of my own build.
My current amp is a 2KW capable Class D stereo power amp. I built a three tube two channel pre-amp to drive it. It has served me well.
Thinking on this I feel that musicians not being able to buy tubes is a small price to pay to support the Ukrainian people in their time of desperate need.
As for the no fly zone that will escalate the situation with a man who has already shown a willingness to start to use nuclear weapons. God help us all if he goes that route. 😖
Personally I don't see those charges as too excessive. Folk do have the right to make a living plus profit. Not to mention the cost of some very specialized and expensive equipment.
Like as not the blown resistor is not the only problem the amp has. Also the circuit board will be easy to damage for the average tinkerer. It requires specialized tools which you won't own.
My advice would be to dispatch the amp to the authorized service provider and get them to repair it. You may be surprised at how cheap it may be.
A thing to remember is that if you want to be twice as loud you'll need to increase power by a factor of ten.
800W is 800W whether derived from a bridged power amp or from a single channel of a larger power amp. The risk of damage depends on the capabilities of the connected speaker system. 800W into a 300W speaker system will eventually cause damage no matter how careful you are.
If the Pod had an XLR it's a pound for a penny that it would have been a low output suitable for connecting to a PA. It would have been quieter that the phone jack. You must remember that many 'on the floor' devices are designed to plug into the front of a bass amp and so have a much lower voltage level than a power amp needs.