for the most part it is indeed only the commands that differ some are even the same as on DOS with maybe a few differences like echo then there are some that we also had in dos like rm=remove cp=copy the unix variants have more options but besides that the functionality is mostly the same dir in unix is called ls though. where linux can still be a bit hard for the uninvited is when it comes to drivers, linux has nothing with the functionality of the device manager from windows and making one is allmost impossible due to how things work in a unix environment. you can get something that shows you installed devices but it does not allow you to change driver parameters or for that matter the driver, you still need to do that with commands. sure back in the DOS days we mostly had to do the same (setting IRQ's DMA etc.) but the commands used were quite a bit simpler as well. where linux would truely shine would be in something with a predetermined hardware set (like a steam deck or steam box) for a gamer atleast, my guess is that is why they decided it would be a good project.
also unix is quite a bit more secure by default than windows, thats not to say you cant get an infection but it is usually not fatal.
also the sheer amount of programs you can get many of which have the same functionality but rely on certain OS gui features (OpenBOX MIR or other variants of the X WIndow system) which not allways play well with the choosen variant you decide to use. In essence it has become a mess and while it is great for those who like as many choices as possible it does have its pitfalls.