Unit has a leak and is low on r22 can we use r22a as a temporary fix

Yes I understand people shouldn't mix refrigerants, we had someone come out and look at our system and basically said we either spend 7-10k+ to replace the system or spend 2k+ to buy enough r22 (8lbs) to top it off. Our unit is ancient and our great grandfather installed it himself in the house. If we can find the leak and fix it... Can we use r22a to top it off so we atleast don't cook to death this summer, and give us some time to save enough money to either replace the system or buy a crap ton of portable AC units or something? The biggest issue is we don't have the money to just up and buy the new central air equipment and having our guy install it.

I'm almost certain our unit is on its last legs, every year seems to be a new problem and it's been maintained with some love taps and wishes lmao. Basically I'm just wondering if it's feasible to use another refrigerant other than r22 to get us to fall/winter? I understand things might be illegal but just because they're illegal doesn't mean they can't be done and work perfectly fine. If r22 wasn't so damn expensive this wouldn't even be an issue but the Canadian government LOVES to just shove their fist up our arses and make our lives even harder, tax us to death to then give us subsidies and government paycheques saying THEY are helping us through economic hardship... When they literally just took $100 out our wallets just to give us $20 as a "relief" payment when that $20 is from OUR MONEY.

Sorry for that little rant lmao I just hate this shit, luckily right now it's not as hot as it was the last few weeks but it seems like there's another heat warning on the way and money is so tight right now. Ive legit considered filling the tub with water and a ton of ice and just to sleep in it during the nights where it doesnt even cool down.