Need help with hot and humid house

So I have a ranch ~1700 sq. feet and half has vaulted ceilings. I've lived here for 13 years and the AC was new when I moved in. The furnace is 16 years old. My home on a hot day has never been able to keep up. The thermostat would be 71 and it'd be 75 in the house. But Now it's in the low 80s. Even when it's like 85 degrees outside.

So I have a couple contractors come out. First one cleans the coils on AC and says I have a refrigerant leak. That was $700, then he says it'll be another $1400 to find the leak/fill with refrigerant. Then maybe another 1500 on top of that to fix the leak. They also just recommended replacing the AC/furnace and I got a quote of 10k for it.

At that point I called another contractor, they filled the refrigerant for $250. While there is improvement on cooling the house, it's still as bad as it was when I first moved in. I'm not sure what the best bang for my buck would be. Windows are older but they are sealed up pretty well. It's just so damn hot and humid in every part of my house until like midnight.

Here is some images of the work order they proposed that I'm debating right now. They also have knocked off another $800 since then. I really appreciate any help you could provide. I work from home and this has gotten real bad lately. Thanks!

https://imgur.com/a/6hJOWmo