It’s all about having good tools if you want to DIY. There are specialty tools for those stupid nuts, or jumbo size channel locks, and you may need to have a opposing force, so the whole unit doesn’t spin and for that there are tools as well, like even needle nose, pliers.
The nut can also be sawn off.
We never ever use the big nut basket strainers any longer, much prefer the three screw variety.