tl;dr Do a lot of non-firing practice, and then still try for live fire but cut down the number of rounds dramatically.
I ran into this problem as well, particularly with 9mm. It’s been much easier to replenish .45, .40, etc. Since I just purchased a new 9mm the problem is even more pronounced as I have to burn through a fair amount of 9mm before declaring it ready for action. But the silver lining of an ammo shortage is it forces me to put in a lot more practice in other areas. Dry practice, jam clearing, and improving my draw are high on the list.
I do use other tools too. I have a wide enough range of other firearms that I don’t have to avoid live firing. I can go to .22 to practice fundamentals, and .45 (which is a primary self-defense round for me, so I practice with it regularly too) for recoil management. I have a LaserLyte training pistol, which I find an awesome training tool…I just wish they had a 1911 version. It has sights modeled on traditional Glock sights, a fairly heavy trigger that approximates a (Gen 1 in my mind) Glock, and a laser burst when it fires that lets you know where you would have hit were it real. You can very effectively practice point shooting, flash sight, and full sight acquisition as well as trigger control. If you really want to work on accuracy, you can get their reactive targets that will only activate if you hit an X-size area. I periodically grab it off my desk and “shoot” something in my office. Or practice in various areas of my downstairs. In addition to their normal Glock style model, they now have a J-Frame style model. So lots of options, but they all involve spending additional $. While buying a .22 version of your normal carry gun has many benefits, any .22 is a useful tool. So if you don’t already have a .22, and don’t have the chunk of change to duplicate your carry gun in .22 or buy the .22 of your dreams, you can probably find a good used one for a lot less than what you’ll spend on a couple of hundred rounds of quality 9mm ammo these days.
But finally, I still am burning through my 9mm ammo I just do so at a much lower rate. So instead of 100 or more rounds at a range session, I’m sticking to 1-2 magazines per session.
PS: bulkammo.com has 500 rounds of 9mm Winchester 115gr FMJ available for $220. While perhaps neither the price you’d like to pay or the best approximation for your chosen self-defense round, it certainly allows continued practice until more preferred options come along.