I had terrible issues my first two seasons of riding. Any time a week went over 8 hours riding time a sore was guaranteed. Any time I got caught out in the rain, a sore was guaranteed. I had a bike fit done, and part of it involved measuring my sit bones, turns out I’m pretty wide. I purchased a wide and flat saddle, the Specialized Power in its widest size, and have never had an issue since. Biggest game changer in my cycling life. If saddle width isn’t your issue, I second all the advice about hygiene before and after riding. Chlorhexidine is pretty amazing stuff they use it for surgical prep. It basically forms an anti microbial barrier that lasts several hours. You can use it before and after your ride. It burns a little, but works really well. If you ask at the pharmacy they’ll be able to direct you to an appropriate product. Until I sorted out the saddle width, the chlorhexedine was a big help. I still use it before and after any 6 hour + rides.
Check your saddle is the correct height, if it’s too high it can cause saddle sores.
+1, this is what helped me. I was getting some unfortunate rubbing when I was properly positioned on the saddle wings, so I tended to slide or rotate forward resulting in moving the problem. A few mm lower saddle position let me sit back and not get the same rub.
A different saddle shape might have helped also, but i’m already on one that curves a lot from the wings to nose.