@Rob93 this is a winner's mindset!
If you feel that 'this application is a massive waste of time if it is not successful' then that attitude is not conducive to keeping up your motivation. You certainly do not need to enjoy any bit about applying, but I found that there is some sort of addictive rhythm to the research and writing process of a law firm application.
And in the process you learn so much about each firm without realising it! I spent hundreds of hours writing applications, most of which was incredibly well-spent time even with hindsight. I now know a huge amount about the London legal market (I have friends who applied to like two firms and were successful, but are now beginning their TCs and facing an extremely steep learning curve). Also, I really enhanced my commercial awareness just by thinking about commercial topics and how they related to law firms.
If you think about each application as an investment in yourself with the added bonus of a possible job coming out of it, then you will be hungry to keep applying