Old Steel Sided Pool, has rust, may need a rebuild

I'm looking for recommendations.
I have an Inground Pool with a concrete bottom, and the old steel-sided walls that occasionally rust. (the pool itself holds 35,000 gallons)
It's been fun, but in 2013 I had to grind off the rust, resurface, and repait.
There was a lot of rust along the seams of the steel walls, but overall, I think they are quite thick.
However, during the last winter, with the cover on, the water level seemed to drop quite a bit, which may indicate a leak.

Even if I grind, and resurface, and paint - this is a recurring problem.

Every pool salesman in the world, will offer me a "Liner" - but I'm not sure I have the proper edging to successfully install a liner, and hold it in place.

I have a preference for DIY solutions - because, Lord Knows, this pool has needed them.
Beyond that, spending $25K for something - if it doesn't work out, is just going to piss me off.
I have quite a bit of sweat equity to offer, and I'm good at finding workers and I know where the local industrial Pool Supply outlet is. Since I'm in Chicago, there's Halogen and a few other as well.
I can also Hire, if there's a qualified vendor, who can solve my problem, within budget.
I'm sure a great vendor can do many things beyond my capabilities.


So I'm considering what I can do to resurface, or shore up the sides.
Or blow in another waterproof layer altogether.
Or install a Liner, if it would even be possible with this pool. (note: nothing at all is wrong with the bottom)
or ____ Add your suggestions here ?? ____

Bonus Points, if you can suggest:
a great rust inhibitor
any general Pool solutions
suggestions for cracked concrete - as shown in the last pictures

I gathered a number of Photos - so I can share this year's Pool Blues with the community, in hope of some good support and ideas. Thank you So Much, for your suggestions, in advance; I do appreciate it.

See the link for the Pool photo gallery -
and each picture will have scroll arrows - to the Left - and to the Right if you hover on the sides.
( thin photos ahve the scroll arrows too - they are just in a different place, so move mouse to the side of photo )

http://mysrv.info/Pool_2018/Pool_1805.html

thanks again

I spent a bit of time researching this, and the feeling I got was that successful liner retrofit parallels my experience locally with using epoxy paint: the local wholesale manager tells me that I am the ONLY local contractor he knows of who has repeatedly used epoxy with good success. Every other contractor does it once, and swears never again.

Apparently, it can be done, but for long term success, prep skills beyond the average pool builder or contractor are required. You might see if Renosys will talk to you. If your IP corresponds to your actual location, they may be close enough to be willing to have a look.

Otherwise, the general impression I got is that some who have done it successfully, have found it hard to make money doing it and have quit. That means that others who will do it . . . may be learning ON YOU that they really don't want to do that kind of work. So, be careful.

Here are some links I found:

http://www.websweeper.com/php/pool_liners/ig-059.php

http://www.websweeper.com/php/pool_liners/ig-059.php

https://www.troublefreepool.com/thre...-a-vinyl-liner