That is probably wise, but let me assure you: The instructions appear complicated and detailed at first sight, but the actual procedure doesn’t take a lot of time. A lot of the instructions are actually about just making sure the prerequisites on your computer are met – and in some cases, they are already given.
I think you didn’t restore a backup after the factory reset but installed from scratch?
Can you define “slow” with any kind of numbers? My FP2 is also becoming slower than at the beginning (even after a factory reset) but I still wouldn’t call it “extremely slow”. I assume apps are often much more demanding for RAM than 5 years ago…
Well, sometimes 10 sec before starting a light app, google chrome taking seconds for every character I type. Links won’t open for mor than 10 seconds. But I guess you are right that apps become more demanding. But I keep trying to find something to make it quicker.
Sounds like you are lucky enough to still have the first revision of the screen. Mine had the same issues, but after I replaced it (it had areas that didn’t respond to touch anymore at all, even without charger) I got a newer revision and since then the issue is gone (it’s charging while I’m writing this). Somewhere in the forum the difference is shown and there are discussions about the charging issue, too. Different chargers didn’t make a big difference for me.
That has become worse and worse and I’m convinced that this is a Spotify issue with the app using more and more memory for basic operations. I can use other apps in parallel that are not too demanding. I usually either listen to Spotify or do something else, so it doesn’t affect me too much luckily. But I totally understand the issue. Try to limit the number of apps that are active (background activity counts, too).