I like the one burner gas one that is dual fuel https://www.amazon.com/GS-3400P-Portable-Backpacking-Emergency-Preparedness/dp/B01HQRD8EO Packs up smaller and I rarely use 2 burners. Although I also carry a MSR Windburner for hot drinks. That way I have a camp stove and backpacking stove for less space. Windburner (or any jetboil type) is a joy to make a hot drink with.
Line conditioners don't really do much. The only thing that is truly effective is a double conversion UPS, which is pricey especially in large sizes.
But the good news is that you don't need one. THD is rarely a problem in real life.
For cooking during outages, I would suggest investing in a tabletop butane stove (these cost all of $30). The latest ones will run on either butane or propane:
https://www.amazon.com/GS-3400P-Portable-Backpacking-Emergency-Preparedness/dp/B01HQRD8EO/
I cannot recommend these things highly enough. Using one is just like cooking on an ordinary gas stove. They are useful even when the power is on. The reason they are so cheap is that they are the ubiquitous cooking appliance of Asia where they are sold by the millions. For $30 it's a no brainer.
FWIW, you don't need a 6000W gen.
I have a butane stove for when I want to cook in an outage.
https://www.amazon.com/GS-3400P-Portable-Backpacking-Emergency-Preparedness/dp/B01HQRD8EO/
These are all of $30.
A bit manual, but I prefer this method over my behmor 1600 (original). Here is my list of parts for a motorized whirley pop:
You would also need some hose clamps and something rigid to stabilize the motor. If you don't have the money to buy another roaster, this is the next best option in my opinion. The hardest part was drilling the hole for the motor shaft. Next time I would torch it.
https://www.amazon.com/dp/B01HQRD8EO/ref=cm_sw_r_cp_apa_fabc_1P65HZEPH4YF51P739TS
Something like this can use both. Butane or get an extra adapter to connect to a big propane tank.