if you have a full time job and do cp in spare time then you truly do this for fun. otherwise it's LARPing. for jobs I do believe you referring dev job SWE or similar, as far as I know blue in cf in minimal and CM is good enough in most situation.

Most competitive programming algorithms are used every day at work. Graphs, sorting, set operations, linear search, combinatorics, segments, intervals. There is no particular point in continuing the competition. You can continue solving problems to the point of “Okay, the solution is already visible, all that’s left to do is type the code. Move to next one.”