Great that you are happy with your decision so far. Here is some of my personal experience with a similar phone and the opinions I formed from it. I hope it will proof helpful for you.
You can setup multiple user profiles on Android and the feature should be even more advanced on GrapheneOS. But there is also Work Profiles on Android and I really hope on GrapheneOS too.
You can create your Work Profile with Insular or Shelter. I use Shelter on CalyxOS. With that you can have the same App twice and isolate work apps and their data from private apps and their data, without ever switching profiles. On iPhone such a feature does not exist, so many people do not know about it.
I don’t use a screen protector and find them to be pretty stupid. They reduce the picture quality of the screen and inhibit sensors like the finger print sensor. They don’t even provide real additional protection, at least in my case. That’s a bad pun, because i use a case to protect my phone from damage. I chose one with extra shock absorption on the four corners, because dropping the phone on a corner is the most likely cause for a broken screen. It also has a lip around the screen. So if the phone lays on screen down on a flat surface, there is a gap of almost one millimeter between the surface and the screen. To keep the phone further protected it just a has it’s own pocket or compartment, in whatever it’s transported in. - That’s what works for me. I never had a broken phone screen. And yes I dropped every phone I had at least once. Even you still believe in screen protectors, I hope you can at least see that there is another way, even if it’s not the one you choose to follow.
For maps and navigation I really like Organic Maps because of it’s sleek interface. I also like OSMAnd~ because of it’s many features, but it is not as sleek and needs much more storage. I used both with offline maps. There are two major downsides compared to Google Maps. You don’t get real time traffic information, which is not an issue for me, because on my usual routes, I would not benefit from it and even Google Maps wouldn’t have actually good data. The other downside is a vastly inferior search function, wich makes finding a location much less convenient. It is not a deal breaker and I still find everything (sometimes with the help of an internet search in my web browser). It is just a little bit annoying.
To find nice Apps you can search on https://f-droid.org/ and https://android.izzysoft.de/repo even if you don’t want to use either of them. They both “app stores“ are at least a comprehensive list of most Open Source Apps out there. There are also “Awesome Open Source Android“ App Lists you can browse through. For beginners, I’d stick to F-Droid. Their selection is (the closest thing to) an trusted catalogue with vetted apps.