With 5 GPUs I get around 5.800 roubles an hour. Fuel from Jeager lasts around 22 hours and costs 157k. That makes it 7.200 roubles/hour. I already invested around 3 million roubles just to set up what I have and I am still going to lose money. If my math is correct, then breaking even with the fuel cost will require 7 GPUs(12 total, so farm lvl2 required). You should either max it out or not bother at all.
The next subject is solar power. Going by the flea prices, I calculated the total cost to be 13.2 million roubles. All it does is halve the fuel drain, so the fuel cost will go from 7.2k/hour to 3.6k/h. Assuming you are running the generator all day long every day, you will save 86.4k roubles a day. After 152 whole days, it will pay for itself. The longest wipe cycle was 214 days long(previous one was 188 days long). The patch dropped 21 days ago which means the next wipe will be 193 days from now at most unless we are now living the longest wipe.
Going by those numbers, you have 41 days left to build the solar power before it is guaranteed to leave you at a loss and if you were to build it today you would save a total of 3.5 million worth of fuel.
tldr: You lose more money than you make by investing in BTC farm and solar power. Go for scav case instead.