Just my take - if you’re planning on playing the same save file for 100s of hours like some people (myself included) the minor bonuses and ‘flex’ factor of an s class freighter can be worth it. For any normal ‘I’m going to play for a while and then move on’ save it’s absolutely not worth it and you shouldn’t worry.
Without save scumming, freighter events occur every 3 hours ish of active play. At a roughly 2% chance in T3 systems that’s 150 hours on AVERAGE. That assumes you’re also warping to a new eligible system every time that internal clock is running out. The only realistic way to get one is the reload method that others have mentioned. It’s up to you whether or not you go that route, I just wanted to emphasize that you really shouldn’t count on ever finding one naturally.
P.s. I think it goes up to 5% in pirate systems but the storage and tech slots are drastically reduced, so it’s kind of a wash time wise since bulkheads are time intensive to acquire.