Rod, sorry you didn't get the job, but glad you're working on improving.
Work can certainly be hit and miss, and I think if your employer doesn't use newer tech at all, it's tough. I would continue to lightly make the case, not argue, but suggest that improvements in some areas can help. That might move things, though very slowly. If nothing else, you're working on your communication and leadership skills by trying to get the boss to do something.
However, at home, the best way to practice that I know is pick a real project and treat as if it's a job. Obviously slower and smaller scale than it might be at work, but still with the same rigorous approach you'd take at work.
For example, if you want to work with Windows Server 2022 at home and build a domain, then treat this as if you were doing it at work. You don't need a lot of machines to do this. You can use free virtualization (Xen/virtualbox/etc) to set up "machines", even on a relatively modest home setup. Bring these up, create accounts, work on managing a domain. It's slow, and it can be frustrating when the machine crawls, but you can do this.
Lots of people have had to purchase their own tools and invest in themselves, even in modest ways. Mechanics go to harbor freight rather than Craftsman. Carpenters look for used tools. Us Tech people can look for deals and make modest investments in hardware that allow us to simulate machines. There are some free tools and resources, like the free $150 you can get from Azure (https://hystax.com/6-tips-and-tricks-to-get-microsoft-azure-free-credits/) or AWS (https://aws.amazon.com/free/). Use what you can and work at a smaller scale, but practice.
Then document. Write a blog on your experiences, what you learn, etc. Do this in Word if you want, but do this so that when someone wants to interview you, you can show your efforts, give them something that shows you're making this effort. A bunch of things you've written, especially online, show that you're motivated and trying, which is impressive to hiring managers.
It's not perfect. Some people will only think that if you haven't done this in a Fortune 500 company, you don't have experience, but more and more, companies do need to hire, and they need people willing to learn if they can't find experienced people. It's hard to prove you're willing to learn from a resume and interview, but you can show this by your efforts.