I've seen a few people online talking about having a dedicated GPS device for mapping, since I don't need a dedicated GPS device for the type of mapping I'm doing, I thought of possibly getting another phone. That's why I came here, I wanted to get another opinion on it and see if it would actually be beneficial.
I have got a second one mainly for mapping, because i want to use a stylus during cold winter (with gloves) and hot summer with sweaty fingers. I hate touch inputs and with the stylus it works easier. This phone also has an SD card slot for all the different map apps, their map data and the OsmTracker photos.
Definitely nothing wrong with that. People have spent way more outrageous amounts of money on other hobbies so just go for it.
If the expense is worth it to you, there is no reason not to. And you'll likely find other uses for the secondary phone too.
If you ever want to do more serious surveying, look into what people are doing with RTK antennas and their smartphones. There are definitely some interesting options for very serious centimeter-accurate surveying that can be done with just a smartphone and an external RTK antenna.
I have a Samsung Galaxy S21 FE which has a lange screen and battery (it works fine for me, only charging to 85%).
I have a bulkier spigen case on it, and have dropped it several times yet, no damage.
I have been thinking about buying an S23 Ultra or a Galaxy fold, but I would just risk to destroy more money.
If I would buy an additional device it would be a used 10" tablet for mapping.
Also an interesting approach would be a #NexDock which I never tried, but might even work like a tablet but as screen and input device for my existing phone, which would make switching during mapping more easy.
At the moment I only do #StreetComplete on the go, and maybe #mapcomplete while sitting in a restaurant for example.