Welcome to the low sodium lifestyle. ;) I only have one kidney left and it is in stage 3 kidney failure, so I'm very motivated to baby it as much as possible. Like others have said, most seasoning blends are not salt-free. But making your own is pretty easy, and so is using individual spices. Ground rosemary is fabulous on potatoes. Garlic and paprika are great on almost everything. I like fresh cilantro in some dishes (not all). Vinegar and lemon juice are also flavor options (check the label, some are higher in sodium than others).
You also need to experiment to see what you can completely give up and what you really want but will have to accept limited amounts of. I love ham and bacon but have completely given up ham and only have a small amount of bacon once in a blue moon. Bye-bye popcorn as well. But I really prefer salted to unsalted butter so I use small amounts of butter. If you and your DW like bread, look into a breadmaker. I found that recipes calling for 2 tsp (or more!) of salt tasted just fine cut down to 1/2 tsp or even 1/4 tsp of salt.
No idea whether you can look forward to getting off oxygen. You didn't say what almost put you in a dirt nap, and it's unlikely anyone here could even make a guess anyway. It depends on whether your heart or lungs suffered permanent damage or whether the damage is reversible and to what degree. I had to come home on oxygen when I suffered a pulmonary embolus but I got off it within a few days.
BTW, my last bloodwork, my creatinine was 1.2. It will probably never get down to normal level again but my lone kidney is doing a bang-up job.