Flipper zero is more aimed at wireless hacking. Which is very cool, it's a fairly unexplored area of hacking (due to traditionally high barrier of entry), but is a subset of "hardware hacking".
For general hardware hacking I'd get a pirate bus ($30), and a saelae logic clone (cheap). Maybe a nice cheap oscilloscope (but they go for $300+), but logic clone can get you mostly there.
I just got my Pokit Pro multimeter in this week and it has an oscilloscope feature. Good for up to 600V. Not currently sure I would recommend it but Ive not found anything bad on it. It is almost $200 now though.
Depends what your trying to do with it to be honest. If you just wanna use the i2c/spi/uart stuff you can probably handle it. If you can plug some cables in, at worst soldering cables or headers to a board and can find the pins/pads themselves you’ll be fine.
At worst if you wanna try it out without spending so much money you can try out the bus pirate from dangerous prototypes it’s only ~27.
It's great for beginners as it has a huge and friendly community behind it and you can easily work your way up from beginner to more intermediate/advanced.
Given all the comments here praising the build quality and conspicuous lack of comments talking about the actual things it can do, I'm guessing it's fairly difficult to use for anything beyond admiring it's build quality
the quickest hit of functionality is duplicating buttons from your remotes.
Next it's fun to mess with the screens at the pub.
Somewhere along the way, realizing that someone out there has the remote you lost long ago and all you really want is an on/off button and now you can get one.
For me so far it's a universal remote with a kind of weird interface.
For general hardware hacking I'd get a pirate bus ($30), and a saelae logic clone (cheap). Maybe a nice cheap oscilloscope (but they go for $300+), but logic clone can get you mostly there.