>>149945713 (OP)Just because you qualify for the UCL one time doesn't mean all the top players in the world will suddenly spead their kegs for you. You just become a feeder club for true top dogs in the sport as they start to notice your team for the first time. See: 2009-2017 Liverpool, Arsenal in the last decade, 2016 Leicester.
I remember Arsenal and Liverpool getting cucked by Man City and Real Madrid for years until they finally built the infrastructure to sustain a strong squad. It's doable but requires smart investing and forward planning. Easier to do when you're already a big club of course, but not impossible. Liverpool almost went bust in 2010 and were a laughing stock since the 90s and look at them now.