It all depends on what are your goals. Why do you even want to learn Unity/GameDev? If its a hobby (and I guess it is) than forcing yourself into doing that is probably not the best thing to do, as with hobby you will always find time limited. So what you want is fun - you need to find fun in what you are doing.
I am on simmilar position - I tried to hit Unity several times, and am getting a little deeper every time. But after a year of break you think you forgot all of it. Its not true - some things stay, even if you dont realise this at the beginning. While it is true, that only constant practice can make you master, its not the only way for the hobbyst. But keeping motivated is hard for someone, who has no real goal (like deadline), so there are some ways of self-motivation. I am not going to write too much about it now, but what I found very interesting is rule of “no zero days”, which means you cannot have a single day while you dont touch your project (or learning materials). You just need to do anything related - be it programming, following tutorial, reading article about Quaternions or maybe designing a part of level or mechanics on a piece of paper if you cannot access your computer.
I personally am not sure what do you mean with features getting deprecated. Its true, that sometimes things go south when you try to open old project on new version. But you can open it with old version of Unity and it should work just fine. Another thing is that you see some new feature and think “Heey, I wish I had that for my game, but damn, it wasn’t here where I started”! So you try to update and everything fails. Dont. You dont need new features on beginner level. I know how it feels. I do. But just forget about it. Go with what you have.
Breaking updates are common in a lot of places now. I had some experience with Oculus Quest for Unity, and that was terrible. Oculus update did break my project twice during 6 months.
Modern Unity looks a little bit lost with plethora of strange paths to take (for example rendering pipelines - how many are now available? 5? Or the new vs Old Input systems), but I think you might have got a little too much of Unity forums or Reddit, where they sometimes complain just a bit too much. I personally don’t like that approach either. But hey… On my level I dont really need that. Stick with one rendering pipeline (I chose URP) and dont care about anythig else. If it gets deprecated and entirely removed in Unity 2024? Who cares honestly? There is going to be something very simmilar, and with small project you and I are able to make as solo-devs its not such a big deal.
Remember to think small. Small games. Not mini-games. Micro games. Find a simple idea for your game. Than reduce it. Than reduce it again to single mechanics. Than simplify it and you will have your first game done and closed. And this step will take you closer to another project. And it will be rewarding if you manage to complete something, even small.
For example like 2 weeks ago I did a little shader in ShaderGraph, that simulates wind on my low-poly trees I made in Blender. Is it optimal shader? I highly doubt it… Is it something really difficult? Its not. Will I ever use it in game? Maybe… Maybe not. Was I happy, that I was able to overcome this issue? Hell yeah. Did I learn something during the process? For sure.
Learning Unity or Game Dev is a process, sometimes harder and tedious, sometimes easier and more rewarding. Remember, that learning something new is always worth it, no matter what it is. Things that you can learn with Unity will apply to other game engines too! Among others there are design patterns, programming patterns, game design skills and knowledge that is exactly the same between all game engines and sometimes even board games. It might seem that nothing overlaps, but its only at early beginner stages. Obviously practice with particular engine will make you better, faster etc in it.
What I can agree, Unreal looks more stable now and maybe even more promising for the future. But for single-indie devs it still might be too much. If you really feel disgusted with Unity, try something else, it wont hurt for sure. I personally dont think its the solution, but well… I can be wrong. Maybe it will click for you with Unreal?