Yes, there are some examples do this without having NIOS II. Please check the examples below:
As per all of your examples, these are in verilog - this is absolutely no help for those of use that do not know verilog - which I why specifically asked if you have any examples in VHDL..
Unfortunately, there isn't a VHDL example to read/write a user flash on MAX 10. But you can open the platform designer and regenerate the Qsys file in VHDL instead of Verilog. Please make sure to review the inclusion of this file into the top level.